configure: preserve various environment variables in config.status

The config.status script is auto-generated by configure upon
completion. The intention is that config.status can be later invoked by
the developer directly, or by make indirectly, to re-detect the same
environment that configure originally used.

The current config.status script, however, only contains a record of the
command line arguments to configure. Various environment variables have
an effect on what configure will find. In particular PKG_CONFIG_LIBDIR &
PKG_CONFIG_PATH vars will affect what libraries pkg-config finds. The
PATH var will affect what toolchain binaries and XXXX-config scripts are
found. The LD_LIBRARY_PATH var will affect what libraries are
found. Most commands have env variables that will override the name/path
of the default version configure finds.

All these key env variables should be recorded in the config.status script.

Autoconf would also preserve CFLAGS, LDFLAGS, LIBS, CPPFLAGS, but QEMU
deals with those differently, expecting extra flags to be set using
configure args, rather than env variables. At the end of the script we
also don't have the original values of those env vars, as we modify them
during configure.

Backports commit e811da7fe229cc17d98b230bdfeaf6d0631ea987 from qemu
This commit is contained in:
Daniel P. Berrangé 2018-10-04 00:46:38 -04:00 committed by Lioncash
parent f3f22c94e1
commit ea64a4629f
No known key found for this signature in database
GPG key ID: 4E3C3CC1031BA9C7

40
qemu/configure vendored
View file

@ -1735,6 +1735,46 @@ cat <<EOD >config.status
# Compiler output produced by configure, useful for debugging
# configure, is in config.log if it exists.
EOD
preserve_env() {
envname=$1
eval envval=\$$envname
if test -n "$envval"
then
echo "$envname='$envval'" >> config.status
echo "export $envname" >> config.status
else
echo "unset $envname" >> config.status
fi
}
# Preserve various env variables that influence what
# features/build target configure will detect
preserve_env AR
preserve_env AS
preserve_env CC
preserve_env CPP
preserve_env CXX
preserve_env INSTALL
preserve_env LD
preserve_env LD_LIBRARY_PATH
preserve_env LIBTOOL
preserve_env MAKE
preserve_env NM
preserve_env OBJCOPY
preserve_env PATH
preserve_env PKG_CONFIG
preserve_env PKG_CONFIG_LIBDIR
preserve_env PKG_CONFIG_PATH
preserve_env PYTHON
preserve_env SDL_CONFIG
preserve_env SDL2_CONFIG
preserve_env SMBD
preserve_env STRIP
preserve_env WINDRES
printf "exec" >>config.status
printf " '%s'" "$0" "$@" >>config.status
echo ' "$@"' >>config.status