tree 4f289ae2cb7358fd58b3c968169f1f417eb63151
parent 2214310d5beaf77a438a808b39402acdbf1a935e
author Stefan Berger <stefanb@linux.ibm.com> 1649076577 -0400
committer Stefan Berger <stefanb@us.ibm.com> 1649113316 -0400

build-sys: Fix configure script to support _FORTIFY_SOURCE=3

gcc 12.1 supports _FORTIFY_SOURCE=3. Modify the existing check for whether
_FORTIFY_SOURCE=2 can be used to test compile with the user provided
CFLAGS and only add _D_FORTIFY_SOURCE=2 to the HARDENING_CFLAGS if the
user doesn't provide anything that's not compatible.

Following an online article _FORTIFY_SOURCE=3 may add more overhead, so
we only go up to level 2 for now and let build servers or user provide
the higher level via the CFLAGS.

https://developers.redhat.com/blog/2021/04/16/broadening-compiler-checks-for-buffer-overflows-in-_fortify_source#what_s_next_for__fortify_source

Resolves: https://github.com/stefanberger/swtpm/issues/688
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>