re: fix build errors on mipsel targets

On most mipsel targets re fails to build because the re Makefile adds
"-march=mips32" to CFLAGS:

Assembler messages:
Error: -mips32r2 conflicts with the other architecture options, which imply -mips32
src/sip/addr.c:1:0: error: '-mips32r2' conflicts with the other architecture options, which specify a mips32 processor
 /**
 ^
Makefile:92: recipe for target 'build-mipsel/sip/addr.o' failed

Fix this by preventing re from adding to OpenWrt CFLAGS.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

libs/re/patches/005-fix-builds-for-mipsel-targets.patch

+--- a/mk/re.mk
++++ b/mk/re.mk
+@@ -448,11 +448,6 @@ endif
+ 
+ CFLAGS	+= -DARCH=\"$(ARCH)\"
+ 
+-ifeq ($(ARCH),mipsel)
+-CFLAGS += -march=mips32
+-endif
+-
+-
+ ##############################################################################
+ #
+ # External libraries section