add _GNU_SOURCE to CPPFLAGS required to include <bits/socket.h> on recent eglibc revisions

SVN-Revision: 17749

package/swconfig/Makefile

@@ -21,6 +21,7 @@ define Package/swconfig
 endef
 
 TARGET_CPPFLAGS := \
+	-D_GNU_SOURCE \
 	-I$(STAGING_DIR)/usr/include/libnl-tiny \
 	-I$(LINUX_DIR)/include \
 	-I$(PKG_BUILD_DIR) \

package/wprobe/Makefile

@@ -61,6 +61,7 @@ define Build/Prepare
 endef
 
 TARGET_CPPFLAGS := \
+	-D_GNU_SOURCE \
 	-I$(STAGING_DIR)/usr/include/libnl-tiny \
 	$(TARGET_CPPFLAGS)