package/gcc: disable libsanitizer with gcc 7.5 and glibc 2.31 toolchain

libsanitizer in gcc 7.x fails to build with glibc 2.31. Fixing it would
require backporting an upstream commit:

    https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=4abc46b51af5751d657764d0c44b8a4aeed06302

However, the backport is not trivial, as there are a lot of conflicts.

Disable libsanitizer since the gcc 7.5 branch is now closed
(unmaintained) and it's not a trivial merge.

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/gcc/gcc.mk

@@ -119,6 +119,16 @@ else
 HOST_GCC_COMMON_CONF_OPTS += --disable-libquadmath
 endif
 
+# Disable libsanitizer due to a build issue with gcc 7.5 and glibc 2.31.
+# It would require to backport the following upstream commit
+# https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=4abc46b51af5751d657764d0c44b8a4aeed06302
+# but it conflict with gcc 7.5 libsanitizer code.
+# Disable libsanitizer since the gcc 7.5 branch is now closed
+# (unmaintained) and it's not a trivial merge.
+ifeq ($(BR2_TOOLCHAIN_BUILDROOT_GLIBC)$(BR2_GCC_VERSION_7_X),yy)
+HOST_GCC_COMMON_CONF_OPTS += --disable-libsanitizer
+endif
+
 # libsanitizer requires wordexp, not in default uClibc config. Also
 # doesn't build properly with musl.
 ifeq ($(BR2_TOOLCHAIN_BUILDROOT_UCLIBC)$(BR2_TOOLCHAIN_BUILDROOT_MUSL),y)