allow flags to be selected based on compiler version

Makefile

@@ -71,7 +71,7 @@ else
       TARGET := beos
     endif
     # BeOS still uses gcc2
-    GCCVER := 2
+    CC_MAJOR := 2
   else
     ifeq ($(HOST),AmigaOS)
       HOST := amiga
@@ -282,6 +282,12 @@ else
   endif
 endif
 
+# compiler versioning to adjust warning flags
+CC_MAJOR := $(shell $(CC) -dumpversion | cut -f1 -d.  )
+CC_MINOR := $(shell $(CC) -dumpversion | cut -f2 -d.  )
+define cc_ver_ge
+$(shell expr $(CC_MAJOR) \>= $(1) \& $(CC_MINOR) \>= $(2))
+endef
 
 # CCACHE
 ifeq ($(origin CCACHE),undefined)
@@ -401,9 +407,13 @@ WARNFLAGS = -W -Wall -Wundef -Wpointer-arith \
 	-Wcast-align -Wwrite-strings -Wstrict-prototypes \
 	-Wmissing-prototypes -Wmissing-declarations -Wredundant-decls \
 	-Wnested-externs -Wuninitialized
-ifneq ($(GCCVER),2)
+ifneq ($(CC_MAJOR),2)
   WARNFLAGS += -Wno-unused-parameter 
 endif
+# deal with lots of unwanted warnings from javascript
+ifeq ($(call cc_ver_ge,4,6),1)
+	WARNFLAGS += -Wno-unused-but-set-variable
+endif
 
 # Pull in the configuration
 include Makefile.defaults

Makefile.sources.javascript

@@ -54,7 +54,6 @@ S_JAVASCRIPT += content.c jsapi.c $(addprefix jsapi/,$(S_JSAPI))
 
 $(eval $(foreach V,$(filter JSAPI_BINDING_%,$(.VARIABLES)),$(call convert_jsapi_binding,$($(V)),$(OBJROOT)/$(patsubst JSAPI_BINDING_%,%,$(V)).c,$(patsubst JSAPI_BINDING_%,%,$(V))_jsapi)))
 
-
 else
 S_JAVASCRIPT += none.c
 endif

monkey/Makefile.target

@@ -33,7 +33,6 @@ $(eval $(call pkg_config_find_and_add_enabled,JS,mozilla-js,JavaScript))
 # no pkg-config for this library
 $(eval $(call feature_enabled,WEBP,-DWITH_WEBP,-lwebp -lvpx,WebP (libwebp)))
 
-#-Wno-unused-but-set-variable
 WARNFLAGS += -Werror
 
 MONKEYCFLAGS := -std=c99 -Dmonkey -Dnsmonkey \