libre: add forgotten define

"OPENWRT" needs to be defined for 001-extend-ninit-nclose-check.patch to
work.

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

libs/re/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=re
 PKG_VERSION:=0.5.6
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.creytiv.com/pub
@@ -45,6 +45,9 @@ endef
 # LD is changed to TARGET_CC to fix build failures on x86 32bit. Without this
 # there's no linking to ssp, which results in undefined references.
 
+# used by 001-extend-ninit-nclose-check.patch
+TARGET_CFLAGS+=-DOPENWRT
+
 ifneq ($(CONFIG_USE_GLIBC)$(CONFIG_USE_MUSL),)
 TARGET_CFLAGS+=-D_GNU_SOURCE
 endif