lwip: fix parentheses equality issue

miri64 · miri64 · commit 68888b91a4f2 · 2018-07-19T14:18:03.000+02:00
Another issue revealed by `llvm`. Since this is caused by the resolution
of a macro in lwIP this can't be solved as a patch, so we just ignore
the warning.
diff --git a/pkg/lwip/Makefile b/pkg/lwip/Makefile
@@ -9,3 +9,7 @@ all: git-download
 	"$(MAKE)" -C $(PKG_BUILDDIR)
 
 include $(RIOTBASE)/pkg/pkg.mk
+
+ifeq (llvm,$(TOOLCHAIN))
+  CFLAGS += -Wno-parentheses-equality
+endif
