package/prboom: Fix big endian fix up

The hack to force big endian support when building
for a big endian machine doesn't work as there is
some whitespace between "#" and "undef" in config.h.

Add a wildcard between those two so that the target
line matches and the replacement is done.

Allows me to play DOOM on my LC475.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/prboom/prboom.mk

@@ -40,7 +40,7 @@ PRBOOM_CONF_OPTS = \
 
 # endianness detection isn't used when cross compiling
 define PRBOOM_BIG_ENDIAN_FIXUP
-	$(SED) 's,.*#undef WORDS_BIGENDIAN.*,#define WORDS_BIGENDIAN 1,g' \
+	$(SED) 's,.*#.*undef WORDS_BIGENDIAN.*,#define WORDS_BIGENDIAN 1,g' \
 		$(PRBOOM_DIR)/config.h
 endef