On 01/19/2012 10:06 AM, Jakub Jelinek wrote:
While the linker test is done using the target linker (it uses default
linker flags btw, so in case a linker would be buggy for one target and not
for a different target also supported by the same linker, it would be
a problem, but let's assume that the linker is either buggy or not for
all targets it supports), AC_PREPROC_IFELSE is done using the host compiler.
For cross-compiling we would need to check the target libc headers.
Ah, right, so the patch is okay.
For glibc we could certainly do something similar to the
case "$target" in
*-*-linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu)
[# glibc 2.4 and later provides __stack_chk_fail and
# either __stack_chk_guard, or TLS access to stack guard canary.
if test -f $target_header_dir/features.h \
&& $EGREP '^[ ]*#[ ]*define[ ]+__GNU_LIBRARY__[
]+([1-9][0-9]|[6-9])' \
$target_header_dir/features.h> /dev/null; then
if $EGREP '^[ ]*#[ ]*define[ ]+__GLIBC__[
]+([1-9][0-9]|[3-9])' \
$target_header_dir/features.h> /dev/null; then
gcc_cv_libc_provides_ssp=yes
elif $EGREP '^[ ]*#[ ]*define[ ]+__GLIBC__[ ]+2' \
$target_header_dir/features.h> /dev/null \
&& $EGREP '^[ ]*#[ ]*define[ ]+__GLIBC_MINOR__[
]+([1-9][0-9]|[4-9])' \
$target_header_dir/features.h> /dev/null; then
gcc_cv_libc_provides_ssp=yes
fi
fi]
Or something like
(cat $target_header_dir/features.h;
echo glibc_so_ver=__GNU_LIBRARY__
echo glibc_ver=__GLIBC__
echo glibc_minor_ver=__GLIBC_MINOR__) | gcc -x c - | \
grep ^glibc.*ver= > glibc-ver.sh
. glibc.sh
which could be moved more easily to a helper macro.
Paolo
