package/prboom: work around gcc bug 85180

With Microblaze Gcc version < 8.x the build hangs due to gcc bug
85180: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85180. The bug
shows up when building prboom with optimization but not when building
with -O0. To work around this, if BR2_TOOLCHAIN_HAS_GCC_BUG_85180=y we
force using -O0.

Fixes:
http://autobuild.buildroot.net/results/e72/e72a2070ab7e9a093c3c70002ee94ee57a6154f6/

Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 801c83da19163a07b91d3a85a56226fd22832501)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/prboom/prboom.mk

@@ -12,6 +12,14 @@ PRBOOM_LICENSE = GPL-2.0+
 PRBOOM_LICENSE_FILES = COPYING
 PRBOOM_AUTORECONF = YES
 
+PRBOOM_CFLAGS = $(TARGET_CFLAGS)
+
+ifeq ($(BR2_TOOLCHAIN_HAS_GCC_BUG_85180),y)
+PRBOOM_CFLAGS += -O0
+endif
+
+PRBOOM_CONF_ENV += CFLAGS="$(PRBOOM_CFLAGS)"
+
 ifeq ($(BR2_PACKAGE_LIBPNG),y)
 PRBOOM_DEPENDENCIES += libpng
 endif