--- a/jni/GNUmakefile
+++ b/jni/GNUmakefile
@@ -41,6 +41,7 @@
 JFFI_BUILD_DIR = $(BUILD_DIR)/jffi
 
 ifeq ($(USE_SYSTEM_LIBFFI),1)
+  LIBFFI =
   LIBFFI_LIBS ?= $(shell pkg-config --libs libffi)
   LIBFFI_CFLAGS ?= $(shell pkg-config --cflags libffi)
 else
@@ -64,9 +65,8 @@
 OFLAGS = -O2 $(JFLAGS)
 
 # MacOS headers aren't completely warning free, so turn them off
-WERROR = -Werror
 ifneq ($(OS),darwin)
-  WFLAGS += -Wundef $(WERROR)
+  WFLAGS += -Wundef
 endif
 WFLAGS += -W -Wall -Wno-unused -Wno-parentheses -Wno-unused-parameter
 PICFLAGS = -fPIC
@@ -279,7 +279,7 @@
 	@echo "JFFI_BUILD_DIR=$(JFFI_BUILD_DIR)"
 	@echo "OBJS=$(OBJS)"
 
-$(LIBJFFI):  $(OBJS) $(LIBFFI_LIBS)
+$(LIBJFFI):  $(OBJS) $(LIBFFI)
 	$(CC) -o $@ $(LDFLAGS) $(SOFLAGS) $(OBJS) $(LIBFFI_LIBS) $(LIBS)
 	$(STRIP) $@
 
@@ -291,7 +291,7 @@
 	@mkdir -p $(@D)
 	@$(CC) $(CFLAGS) -o $@ -c $<
 
-$(OBJS) : $(LIBFFI_LIBS)
+$(OBJS) : $(LIBFFI)
 
 ifeq ($(OS), darwin)
 build_ffi = \
--- a/libtest/GNUmakefile
+++ b/libtest/GNUmakefile
@@ -44,8 +44,8 @@
 # Compiler/linker flags from:
 #   http://weblogs.java.net/blog/kellyohair/archive/2006/01/compilation_of_1.html
 JFLAGS = -fno-omit-frame-pointer -fno-strict-aliasing
-OFLAGS = -O2 $(JFLAGS)
-WFLAGS = -W -Werror -Wall -Wno-unused -Wno-unused-parameter -Wno-parentheses
+OFLAGS = $(JFLAGS)
+WFLAGS = -W -Wall -Wno-unused -Wno-unused-parameter -Wno-parentheses
 PICFLAGS = -fPIC
 SOFLAGS = -shared -Wl,-O1
 LDFLAGS += $(SOFLAGS)