package/dmalloc: re-enable package on microblaze

Building dmalloc on Microblaze with optimization enabled and gcc < 8.x
fails with:

  Error: operation combines symbols in different segments

This is due to gcc bug 63261 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63261).

To avoid this, the dmalloc package has a !BR2_microblaze
dependency. However, gcc bug 63261 only triggers when optimization is
enabled, so we can work around the issue by passing -O0, which is what
we do in other Buildroot packages to work around this bug.

So, this commit passes -O0 when BR2_TOOLCHAIN_HAS_GCC_BUG_63261, and
re-enables dmalloc on Microblaze.

Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/dmalloc/Config.in

@@ -1,9 +1,5 @@
 config BR2_PACKAGE_DMALLOC
 	bool "dmalloc"
-	# On some packages, Microblaze gcc has issues when debugging
-	# symbols are enabled: "Error: operation combines symbols in
-	# different segments".
-	depends on !(BR2_microblaze && BR2_ENABLE_DEBUG)
 	help
 	  A debug memory allocation library which is a drop in
 	  replacement for the system's malloc, realloc, calloc, free and

package/dmalloc/dmalloc.mk

@@ -35,6 +35,10 @@ ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
 DMALLOC_CFLAGS += -marm
 endif
 
+ifeq ($(BR2_TOOLCHAIN_HAS_GCC_BUG_63261),y)
+DMALLOC_CFLAGS += -O0
+endif
+
 DMALLOC_CONF_ENV = CFLAGS="$(DMALLOC_CFLAGS)"
 
 define DMALLOC_POST_PATCH