Merge bitcoin/bitcoin#27061: doc: Document affected gcc versions for -fstack-reuse=none workaround

fa83005 doc: Document affected gcc versions for -fstack-reuse=none workaround (MarcoFalke)

Pull request description:

  gcc version(s) 11 and prior won't be fixed, looking at the activity in the bug report. So it seems best to just document gcc 12.1+ as fixed, so that in the future the workaround can be removed once the minimum compiler is gcc12.1.

ACKs for top commit:
  fanquake:
    ACK fa83005
  hebasto:
    re-ACK fa83005

Tree-SHA512: a19723457eb1925196828a5fafd4e7f75a04f86ffae63cb86679d732c662fd1a22e17fe3c69195a97438ff189ba3ff681be3650cf99aa195d7a3e89cd8ee137c

Author: fanquake

configure.ac

@@ -935,7 +935,9 @@ if test "$TARGET_OS" != "windows"; then
   AX_CHECK_COMPILE_FLAG([-fPIC], [PIC_FLAGS="-fPIC"])
 fi
 
-dnl All versions of gcc that we commonly use for building are subject to bug
+dnl Versions of gcc prior to 12.1 (commit
+dnl https://github.com/gcc-mirror/gcc/commit/551aa75778a4c5165d9533cd447c8fc822f583e1)
+dnl are subject to a bug, see the gccbug_90348 test case and
 dnl https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90348. To work around that, set
 dnl -fstack-reuse=none for all gcc builds. (Only gcc understands this flag)
 AX_CHECK_COMPILE_FLAG([-fstack-reuse=none], [HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fstack-reuse=none"])