diff --git a/Makefile.am b/Makefile.am
index 7771a6e3..4a8ee4af 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -43,18 +43,7 @@ AM_CXXFLAGS += -I$(top_srcdir)/src/common/android/include
 AM_CXXFLAGS += -I$(top_srcdir)/src/common/android/testing/include
 endif
 
-if GCC
-# These are good warnings to be treated as errors
-AM_CXXFLAGS += \
-	-Werror \
-	-Werror=missing-braces \
-	-Werror=non-virtual-dtor \
-	-Werror=overloaded-virtual \
-	-Werror=reorder \
-	-Werror=sign-compare \
-	-Werror=unused-variable \
-	-Werror=vla
-endif
+AM_CXXFLAGS += $(WARN_CXXFLAGS)
 
 if LINUX_HOST
 # Build as PIC on Linux, for linux_client_unittest_shlib
diff --git a/Makefile.in b/Makefile.in
index 2de8fd3e..84206074 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -129,53 +129,41 @@ host_triplet = @host@
 @ANDROID_HOST_TRUE@	-I$(top_srcdir)/src/common/android/include \
 @ANDROID_HOST_TRUE@	-I$(top_srcdir)/src/common/android/testing/include
 
-# These are good warnings to be treated as errors
-@GCC_TRUE@am__append_2 = \
-@GCC_TRUE@	-Werror \
-@GCC_TRUE@	-Werror=missing-braces \
-@GCC_TRUE@	-Werror=non-virtual-dtor \
-@GCC_TRUE@	-Werror=overloaded-virtual \
-@GCC_TRUE@	-Werror=reorder \
-@GCC_TRUE@	-Werror=sign-compare \
-@GCC_TRUE@	-Werror=unused-variable \
-@GCC_TRUE@	-Werror=vla
-
-
 # Build as PIC on Linux, for linux_client_unittest_shlib
+@LINUX_HOST_TRUE@am__append_2 = -fPIC
 @LINUX_HOST_TRUE@am__append_3 = -fPIC
-@LINUX_HOST_TRUE@am__append_4 = -fPIC
 bin_PROGRAMS = $(am__EXEEXT_2) $(am__EXEEXT_3) $(am__EXEEXT_4)
 check_PROGRAMS = $(am__EXEEXT_5) $(am__EXEEXT_6) $(am__EXEEXT_7) \
 	$(am__EXEEXT_8) $(am__EXEEXT_9)
 EXTRA_PROGRAMS = $(am__EXEEXT_1)
-@DISABLE_PROCESSOR_FALSE@am__append_5 = src/libbreakpad.a
-@DISABLE_PROCESSOR_FALSE@am__append_6 = breakpad.pc
-@DISABLE_PROCESSOR_FALSE@am__append_7 = src/third_party/libdisasm/libdisasm.a
-@LINUX_HOST_TRUE@am__append_8 = src/client/linux/libbreakpad_client.a
-@LINUX_HOST_TRUE@am__append_9 = breakpad-client.pc
-@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_10 = \
+@DISABLE_PROCESSOR_FALSE@am__append_4 = src/libbreakpad.a
+@DISABLE_PROCESSOR_FALSE@am__append_5 = breakpad.pc
+@DISABLE_PROCESSOR_FALSE@am__append_6 = src/third_party/libdisasm/libdisasm.a
+@LINUX_HOST_TRUE@am__append_7 = src/client/linux/libbreakpad_client.a
+@LINUX_HOST_TRUE@am__append_8 = breakpad-client.pc
+@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_9 = \
 @ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@	src/common/android/breakpad_getcontext.S
 
-@DISABLE_PROCESSOR_FALSE@am__append_11 = \
+@DISABLE_PROCESSOR_FALSE@am__append_10 = \
 @DISABLE_PROCESSOR_FALSE@	src/processor/microdump_stackwalk \
 @DISABLE_PROCESSOR_FALSE@	src/processor/minidump_dump \
 @DISABLE_PROCESSOR_FALSE@	src/processor/minidump_stackwalk
 
+@LINUX_HOST_TRUE@am__append_11 = src/client/linux/linux_dumper_unittest_helper \
+@LINUX_HOST_TRUE@	src/client/linux/linux_client_unittest_shlib
 @LINUX_HOST_TRUE@am__append_12 = src/client/linux/linux_dumper_unittest_helper \
 @LINUX_HOST_TRUE@	src/client/linux/linux_client_unittest_shlib
-@LINUX_HOST_TRUE@am__append_13 = src/client/linux/linux_dumper_unittest_helper \
-@LINUX_HOST_TRUE@	src/client/linux/linux_client_unittest_shlib
-@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@am__append_14 = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@am__append_13 = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/core2md/core2md \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/dump_syms/dump_syms \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/md2core/minidump-2-core \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/symupload/minidump_upload \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/symupload/sym_upload
 
-@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@am__append_15 = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@am__append_14 = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@	src/tools/mac/dump_syms/dump_syms_mac
 
-@DISABLE_PROCESSOR_FALSE@am__append_16 = \
+@DISABLE_PROCESSOR_FALSE@am__append_15 = \
 @DISABLE_PROCESSOR_FALSE@	src/common/test_assembler_unittest \
 @DISABLE_PROCESSOR_FALSE@	src/processor/address_map_unittest \
 @DISABLE_PROCESSOR_FALSE@	src/processor/basic_source_line_resolver_unittest \
@@ -206,36 +194,41 @@ EXTRA_PROGRAMS = $(am__EXEEXT_1)
 @DISABLE_PROCESSOR_FALSE@	src/processor/stackwalker_x86_unittest \
 @DISABLE_PROCESSOR_FALSE@	src/processor/synth_minidump_unittest
 
-@LINUX_HOST_TRUE@am__append_17 = \
+@LINUX_HOST_TRUE@am__append_16 = \
 @LINUX_HOST_TRUE@	src/client/linux/linux_client_unittest
 
-@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@am__append_18 = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@am__append_17 = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/common/dumper_unittest \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@	src/tools/linux/md2core/minidump_2_core_unittest
 
-@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@am__append_19 = \
+@DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@am__append_18 = \
 @DISABLE_TOOLS_FALSE@@LINUX_HOST_TRUE@@X86_HOST_TRUE@	src/common/mac/macho_reader_unittest
 
-@DISABLE_PROCESSOR_FALSE@@SELFTEST_TRUE@am__append_20 = \
+@DISABLE_PROCESSOR_FALSE@@SELFTEST_TRUE@am__append_19 = \
 @DISABLE_PROCESSOR_FALSE@@SELFTEST_TRUE@	src/processor/stackwalker_selftest
 
-@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_21 = \
+@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_20 = \
 @ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@	src/common/android/breakpad_getcontext.S
 
-@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_22 = \
+@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_21 = \
 @ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@	src/common/android/breakpad_getcontext_unittest.cc
 
-@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_23 = \
+@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_22 = \
 @ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@	-llog -lm
 
-@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_24 = \
+@ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@am__append_23 = \
 @ANDROID_HOST_TRUE@@LINUX_HOST_TRUE@        -llog
 
 noinst_PROGRAMS =
 subdir = .
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
-am__aclocal_m4_deps = $(top_srcdir)/m4/ax_cxx_compile_stdcxx.m4 \
-	$(top_srcdir)/m4/ax_pthread.m4 $(top_srcdir)/configure.ac
+am__aclocal_m4_deps = $(top_srcdir)/m4/ax_append_compile_flags.m4 \
+	$(top_srcdir)/m4/ax_append_flag.m4 \
+	$(top_srcdir)/m4/ax_check_compile_flag.m4 \
+	$(top_srcdir)/m4/ax_cxx_compile_stdcxx.m4 \
+	$(top_srcdir)/m4/ax_pthread.m4 \
+	$(top_srcdir)/m4/ax_require_defined.m4 \
+	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 DIST_COMMON = $(srcdir)/Makefile.am $(top_srcdir)/configure \
@@ -1963,6 +1956,7 @@ SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
 STRIP = @STRIP@
 VERSION = @VERSION@
+WARN_CXXFLAGS = @WARN_CXXFLAGS@
 abs_builddir = @abs_builddir@
 abs_srcdir = @abs_srcdir@
 abs_top_builddir = @abs_top_builddir@
@@ -2019,8 +2013,8 @@ top_srcdir = @top_srcdir@
 
 # This allows #includes to be relative to src/
 AM_CPPFLAGS = -I$(top_srcdir)/src
-AM_CFLAGS = $(am__append_3)
-AM_CXXFLAGS = $(am__append_1) $(am__append_2) $(am__append_4)
+AM_CFLAGS = $(am__append_2)
+AM_CXXFLAGS = $(am__append_1) $(WARN_CXXFLAGS) $(am__append_3)
 
 # Specify include paths for ac macros
 ACLOCAL_AMFLAGS = -I m4
@@ -2054,7 +2048,7 @@ includec_HEADERS = $(top_srcdir)/src/common/*.h
 includepdir = $(includedir)/$(PACKAGE)/processor
 includep_HEADERS = $(top_srcdir)/src/processor/*.h
 pkgconfigdir = $(libdir)/pkgconfig
-pkgconfig_DATA = $(am__append_6) $(am__append_9)
+pkgconfig_DATA = $(am__append_5) $(am__append_8)
 @SYSTEM_TEST_LIBS_FALSE@TEST_CFLAGS = \
 @SYSTEM_TEST_LIBS_FALSE@	-I$(top_srcdir)/src/testing/include \
 @SYSTEM_TEST_LIBS_FALSE@	-I$(top_srcdir)/src/testing/googletest/include \
@@ -2069,9 +2063,9 @@ pkgconfig_DATA = $(am__append_6) $(am__append_9)
 @SYSTEM_TEST_LIBS_FALSE@TEST_DEPS = $(TEST_LIBS)
 @SYSTEM_TEST_LIBS_TRUE@TEST_DEPS = 
 check_LIBRARIES = src/testing/libtesting.a
-noinst_LIBRARIES = $(am__append_7)
-lib_LIBRARIES = $(am__append_5) $(am__append_8)
-CLEANFILES = $(am__append_13)
+noinst_LIBRARIES = $(am__append_6)
+lib_LIBRARIES = $(am__append_4) $(am__append_7)
+CLEANFILES = $(am__append_12)
 @SYSTEM_TEST_LIBS_FALSE@src_testing_libtesting_a_SOURCES = \
 @SYSTEM_TEST_LIBS_FALSE@	src/breakpad_googletest_includes.h \
 @SYSTEM_TEST_LIBS_FALSE@	src/testing/googletest/src/gtest-all.cc \
@@ -2115,7 +2109,7 @@ CLEANFILES = $(am__append_13)
 @LINUX_HOST_TRUE@	src/common/linux/linux_libc_support.cc \
 @LINUX_HOST_TRUE@	src/common/linux/memory_mapped_file.cc \
 @LINUX_HOST_TRUE@	src/common/linux/safe_readlink.cc \
-@LINUX_HOST_TRUE@	$(am__append_10)
+@LINUX_HOST_TRUE@	$(am__append_9)
 @DISABLE_PROCESSOR_FALSE@src_libbreakpad_a_SOURCES = \
 @DISABLE_PROCESSOR_FALSE@	src/google_breakpad/common/breakpad_types.h \
 @DISABLE_PROCESSOR_FALSE@	src/google_breakpad/common/minidump_format.h \
@@ -2312,15 +2306,15 @@ TESTS = $(check_PROGRAMS) $(check_SCRIPTS)
 @LINUX_HOST_TRUE@	src/processor/minidump.cc \
 @LINUX_HOST_TRUE@	src/processor/pathname_stripper.cc \
 @LINUX_HOST_TRUE@	src/processor/proc_maps_linux.cc \
-@LINUX_HOST_TRUE@	$(am__append_21) \
+@LINUX_HOST_TRUE@	$(am__append_20) \
 @LINUX_HOST_TRUE@	src/client/linux/microdump_writer/microdump_writer_unittest.cc \
-@LINUX_HOST_TRUE@	$(am__append_22)
+@LINUX_HOST_TRUE@	$(am__append_21)
 @LINUX_HOST_TRUE@src_client_linux_linux_client_unittest_shlib_CPPFLAGS = \
 @LINUX_HOST_TRUE@	$(AM_CPPFLAGS) $(TEST_CFLAGS)
 
 @LINUX_HOST_TRUE@src_client_linux_linux_client_unittest_shlib_LDFLAGS =  \
 @LINUX_HOST_TRUE@	-shared -Wl,-h,linux_client_unittest_shlib \
-@LINUX_HOST_TRUE@	$(am__append_23)
+@LINUX_HOST_TRUE@	$(am__append_22)
 @LINUX_HOST_TRUE@src_client_linux_linux_client_unittest_shlib_LDADD = \
 @LINUX_HOST_TRUE@	src/client/linux/crash_generation/crash_generation_client.o \
 @LINUX_HOST_TRUE@	src/client/linux/dump_writer_common/thread_info.o \
@@ -2356,7 +2350,7 @@ TESTS = $(check_PROGRAMS) $(check_SCRIPTS)
 @LINUX_HOST_TRUE@src_client_linux_linux_client_unittest_LDFLAGS =  \
 @LINUX_HOST_TRUE@	-Wl,-rpath,'$$ORIGIN' \
 @LINUX_HOST_TRUE@	-Wl,--build-id=0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f \
-@LINUX_HOST_TRUE@	$(am__append_24)
+@LINUX_HOST_TRUE@	$(am__append_23)
 @LINUX_HOST_TRUE@src_client_linux_linux_client_unittest_LDADD = \
 @LINUX_HOST_TRUE@	src/client/linux/linux_client_unittest_shlib \
 @LINUX_HOST_TRUE@	$(TEST_LIBS)
diff --git a/aclocal.m4 b/aclocal.m4
index 9b17609b..16992bfd 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1295,5 +1295,9 @@ AC_SUBST([am__tar])
 AC_SUBST([am__untar])
 ]) # _AM_PROG_TAR
 
+m4_include([m4/ax_append_compile_flags.m4])
+m4_include([m4/ax_append_flag.m4])
+m4_include([m4/ax_check_compile_flag.m4])
 m4_include([m4/ax_cxx_compile_stdcxx.m4])
 m4_include([m4/ax_pthread.m4])
+m4_include([m4/ax_require_defined.m4])
diff --git a/configure b/configure
index 3de6e284..8d92159f 100755
--- a/configure
+++ b/configure
@@ -648,6 +648,7 @@ ANDROID_HOST_FALSE
 ANDROID_HOST_TRUE
 LINUX_HOST_FALSE
 LINUX_HOST_TRUE
+WARN_CXXFLAGS
 HAVE_CXX11
 PTHREAD_CFLAGS
 PTHREAD_LIBS
@@ -655,8 +656,6 @@ PTHREAD_CC
 ax_pthread_config
 EGREP
 GREP
-GCC_FALSE
-GCC_TRUE
 RANLIB
 am__fastdepCXX_FALSE
 am__fastdepCXX_TRUE
@@ -5737,14 +5736,6 @@ else
   RANLIB="$ac_cv_prog_RANLIB"
 fi
 
- if test "$GCC" = yes; then
-  GCC_TRUE=
-  GCC_FALSE='#'
-else
-  GCC_TRUE='#'
-  GCC_FALSE=
-fi
-   # let the Makefile know if we're gcc
 
 # Check whether --enable-m32 was given.
 if test "${enable_m32+set}" = set; then :
@@ -7254,6 +7245,136 @@ $as_echo "#define HAVE_CXX11 1" >>confdefs.h
   fi
 
 
+WARN_CXXFLAGS=
+ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C++ compiler accepts -Werror=unknown-warning-option" >&5
+$as_echo_n "checking whether C++ compiler accepts -Werror=unknown-warning-option... " >&6; }
+if ${ax_cv_check_cxxflags___Werror_unknown_warning_option+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+  ax_check_save_flags=$CXXFLAGS
+  CXXFLAGS="$CXXFLAGS  -Werror=unknown-warning-option"
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  ax_cv_check_cxxflags___Werror_unknown_warning_option=yes
+else
+  ax_cv_check_cxxflags___Werror_unknown_warning_option=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  CXXFLAGS=$ax_check_save_flags
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_check_cxxflags___Werror_unknown_warning_option" >&5
+$as_echo "$ax_cv_check_cxxflags___Werror_unknown_warning_option" >&6; }
+if test "x$ax_cv_check_cxxflags___Werror_unknown_warning_option" = xyes; then :
+
+  ax_compiler_flags_test="-Werror=unknown-warning-option"
+
+else
+
+  ax_compiler_flags_test=""
+
+fi
+
+
+
+
+
+for flag in    -Wmissing-braces   -Wnon-virtual-dtor   -Woverloaded-virtual   -Wreorder   -Wsign-compare   -Wunused-variable   -Wvla ; do
+  as_CACHEVAR=`$as_echo "ax_cv_check_cxxflags_${ax_compiler_flags_test}_$flag" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C++ compiler accepts $flag" >&5
+$as_echo_n "checking whether C++ compiler accepts $flag... " >&6; }
+if eval \${$as_CACHEVAR+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+  ax_check_save_flags=$CXXFLAGS
+  CXXFLAGS="$CXXFLAGS ${ax_compiler_flags_test} $flag"
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  eval "$as_CACHEVAR=yes"
+else
+  eval "$as_CACHEVAR=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  CXXFLAGS=$ax_check_save_flags
+fi
+eval ac_res=\$$as_CACHEVAR
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_CACHEVAR"\" = x"yes"; then :
+
+if ${WARN_CXXFLAGS+:} false; then :
+
+  case " $WARN_CXXFLAGS " in #(
+  *" $flag "*) :
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: : WARN_CXXFLAGS already contains \$flag"; } >&5
+  (: WARN_CXXFLAGS already contains $flag) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } ;; #(
+  *) :
+
+     as_fn_append WARN_CXXFLAGS " $flag"
+     { { $as_echo "$as_me:${as_lineno-$LINENO}: : WARN_CXXFLAGS=\"\$WARN_CXXFLAGS\""; } >&5
+  (: WARN_CXXFLAGS="$WARN_CXXFLAGS") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+     ;;
+esac
+
+else
+
+  WARN_CXXFLAGS=$flag
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: : WARN_CXXFLAGS=\"\$WARN_CXXFLAGS\""; } >&5
+  (: WARN_CXXFLAGS="$WARN_CXXFLAGS") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+
+fi
+
+else
+  :
+fi
+
+done
+
+as_fn_append WARN_CXXFLAGS " -Werror"
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
 # Only build Linux client libs when compiling for Linux
 case $host in
   *-*-linux* | *-android* )
@@ -7780,10 +7901,6 @@ if test -z "${am__fastdepCXX_TRUE}" && test -z "${am__fastdepCXX_FALSE}"; then
   as_fn_error $? "conditional \"am__fastdepCXX\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
-if test -z "${GCC_TRUE}" && test -z "${GCC_FALSE}"; then
-  as_fn_error $? "conditional \"GCC\" was never defined.
-Usually this means the macro was only invoked conditionally." "$LINENO" 5
-fi
 if test -z "${LINUX_HOST_TRUE}" && test -z "${LINUX_HOST_FALSE}"; then
   as_fn_error $? "conditional \"LINUX_HOST\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
diff --git a/configure.ac b/configure.ac
index c2dc7b3f..8dd855d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -28,7 +28,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-AC_PREREQ(2.57)
+AC_PREREQ(2.64)
 
 AC_INIT(breakpad, 0.1, google-breakpad-dev@googlegroups.com)
 dnl Sanity check: the argument is just a file that should exist.
@@ -48,7 +48,6 @@ AM_PROG_CC_C_O
 AC_PROG_CPP
 AC_PROG_CXX
 AC_PROG_RANLIB
-AM_CONDITIONAL(GCC, test "$GCC" = yes)   # let the Makefile know if we're gcc
 
 dnl This must come before all the feature tests below.
 AC_ARG_ENABLE(m32,
@@ -77,6 +76,29 @@ AC_CHECK_HEADERS([a.out.h])
 
 AX_CXX_COMPILE_STDCXX(11, noext, mandatory)
 
+dnl Test supported warning flags.
+WARN_CXXFLAGS=
+dnl This warning flag is used by clang.  Its default behavior is to warn when
+dnl given an unknown flag rather than error out.
+AC_LANG_PUSH([C++])
+AX_CHECK_COMPILE_FLAG([-Werror=unknown-warning-option],[
+  ax_compiler_flags_test="-Werror=unknown-warning-option"
+],[
+  ax_compiler_flags_test=""
+])
+AX_APPEND_COMPILE_FLAGS(m4_flatten([
+  -Wmissing-braces
+  -Wnon-virtual-dtor
+  -Woverloaded-virtual
+  -Wreorder
+  -Wsign-compare
+  -Wunused-variable
+  -Wvla
+]), [WARN_CXXFLAGS], [${ax_compiler_flags_test}])
+AS_VAR_APPEND([WARN_CXXFLAGS], " -Werror")
+AC_LANG_POP([C++])
+AC_SUBST([WARN_CXXFLAGS])
+
 # Only build Linux client libs when compiling for Linux
 case $host in
   *-*-linux* | *-android* )
diff --git a/m4/ax_append_compile_flags.m4 b/m4/ax_append_compile_flags.m4
new file mode 100644
index 00000000..2bb27ef2
--- /dev/null
+++ b/m4/ax_append_compile_flags.m4
@@ -0,0 +1,67 @@
+# ===========================================================================
+#  http://www.gnu.org/software/autoconf-archive/ax_append_compile_flags.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_APPEND_COMPILE_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   For every FLAG1, FLAG2 it is checked whether the compiler works with the
+#   flag.  If it does, the flag is added FLAGS-VARIABLE
+#
+#   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
+#   CFLAGS) is used.  During the check the flag is always added to the
+#   current language's flags.
+#
+#   If EXTRA-FLAGS is defined, it is added to the current language's default
+#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with
+#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
+#   force the compiler to issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
+#   NOTE: This macro depends on the AX_APPEND_FLAG and
+#   AX_CHECK_COMPILE_FLAG. Please keep this macro in sync with
+#   AX_APPEND_LINK_FLAGS.
+#
+# LICENSE
+#
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 5
+
+AC_DEFUN([AX_APPEND_COMPILE_FLAGS],
+[AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG])
+AX_REQUIRE_DEFINED([AX_APPEND_FLAG])
+for flag in $1; do
+  AX_CHECK_COMPILE_FLAG([$flag], [AX_APPEND_FLAG([$flag], [$2])], [], [$3], [$4])
+done
+])dnl AX_APPEND_COMPILE_FLAGS
diff --git a/m4/ax_append_flag.m4 b/m4/ax_append_flag.m4
new file mode 100644
index 00000000..08f2e07e
--- /dev/null
+++ b/m4/ax_append_flag.m4
@@ -0,0 +1,71 @@
+# ===========================================================================
+#      http://www.gnu.org/software/autoconf-archive/ax_append_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_APPEND_FLAG(FLAG, [FLAGS-VARIABLE])
+#
+# DESCRIPTION
+#
+#   FLAG is appended to the FLAGS-VARIABLE shell variable, with a space
+#   added in between.
+#
+#   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
+#   CFLAGS) is used.  FLAGS-VARIABLE is not changed if it already contains
+#   FLAG.  If FLAGS-VARIABLE is unset in the shell, it is set to exactly
+#   FLAG.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 6
+
+AC_DEFUN([AX_APPEND_FLAG],
+[dnl
+AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IF
+AS_VAR_PUSHDEF([FLAGS], [m4_default($2,_AC_LANG_PREFIX[FLAGS])])
+AS_VAR_SET_IF(FLAGS,[
+  AS_CASE([" AS_VAR_GET(FLAGS) "],
+    [*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
+    [
+     AS_VAR_APPEND(FLAGS,[" $1"])
+     AC_RUN_LOG([: FLAGS="$FLAGS"])
+    ])
+  ],
+  [
+  AS_VAR_SET(FLAGS,[$1])
+  AC_RUN_LOG([: FLAGS="$FLAGS"])
+  ])
+AS_VAR_POPDEF([FLAGS])dnl
+])dnl AX_APPEND_FLAG
diff --git a/m4/ax_check_compile_flag.m4 b/m4/ax_check_compile_flag.m4
new file mode 100644
index 00000000..ca363971
--- /dev/null
+++ b/m4/ax_check_compile_flag.m4
@@ -0,0 +1,74 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   Check whether the given FLAG works with the current language's compiler
+#   or gives an error.  (Warnings, however, are ignored)
+#
+#   ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+#   success/failure.
+#
+#   If EXTRA-FLAGS is defined, it is added to the current language's default
+#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with
+#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
+#   force the compiler to issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
+#   macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 4
+
+AC_DEFUN([AX_CHECK_COMPILE_FLAG],
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
+  ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
+  _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
+  AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
+    [AS_VAR_SET(CACHEVAR,[yes])],
+    [AS_VAR_SET(CACHEVAR,[no])])
+  _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
+AS_VAR_IF(CACHEVAR,yes,
+  [m4_default([$2], :)],
+  [m4_default([$3], :)])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_COMPILE_FLAGS
diff --git a/m4/ax_require_defined.m4 b/m4/ax_require_defined.m4
new file mode 100644
index 00000000..cae11112
--- /dev/null
+++ b/m4/ax_require_defined.m4
@@ -0,0 +1,37 @@
+# ===========================================================================
+#    http://www.gnu.org/software/autoconf-archive/ax_require_defined.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_REQUIRE_DEFINED(MACRO)
+#
+# DESCRIPTION
+#
+#   AX_REQUIRE_DEFINED is a simple helper for making sure other macros have
+#   been defined and thus are available for use.  This avoids random issues
+#   where a macro isn't expanded.  Instead the configure script emits a
+#   non-fatal:
+#
+#     ./configure: line 1673: AX_CFLAGS_WARN_ALL: command not found
+#
+#   It's like AC_REQUIRE except it doesn't expand the required macro.
+#
+#   Here's an example:
+#
+#     AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])
+#
+# LICENSE
+#
+#   Copyright (c) 2014 Mike Frysinger <vapier@gentoo.org>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 1
+
+AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
+  m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file missing?])])
+])dnl AX_REQUIRE_DEFINED