gcc: don't patch gcc if there are no patches to apply

While the generic package handler checks for a directory with patches
before starting apply-patches.sh, this is not the case for gcc: the
script is called, even if there is no directory with patches. This results
into a build failure, as apply-patches exits with error code 1 if the
directory doesn't exist.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gcc/gcc.mk

@@ -49,7 +49,9 @@ endif
 endif
 
 define HOST_GCC_APPLY_PATCHES
-	support/scripts/apply-patches.sh $(@D) package/gcc/$(GCC_VERSION) \*.patch
+	if test -d package/gcc/$(GCC_VERSION); then \
+	  support/scripts/apply-patches.sh $(@D) package/gcc/$(GCC_VERSION) \*.patch ; \
+	fi;
 	$(HOST_GCC_APPLY_POWERPC_PATCH)
 endef