diff --git a/vm/Config.macosx b/vm/Config.macosx
index f8458bb772..babe792218 100644
--- a/vm/Config.macosx
+++ b/vm/Config.macosx
@@ -1,5 +1,5 @@
 include vm/Config.unix
-CFLAGS += -fPIC
+SITE_CFLAGS +=
 
 PLAF_DLL_OBJS += vm/os-macosx.o vm/mach_signal.o vm/mvm-unix.o
 PLAF_MASTER_HEADERS += vm/os-macosx.hpp vm/mach_signal.hpp
diff --git a/vm/Config.macosx.x86.fat b/vm/Config.macosx.x86.fat
index 9b3c158cb9..e8a0e10d9f 100644
--- a/vm/Config.macosx.x86.fat
+++ b/vm/Config.macosx.x86.fat
@@ -1,3 +1,3 @@
 include vm/Config.macosx
 include vm/Config.x86.fat
-CFLAGS += -arch i386 -arch x86_64
+SITE_CFLAGS += -arch i386 -arch x86_64
diff --git a/vm/Config.unix b/vm/Config.unix
index 8a36522619..9b11289162 100644
--- a/vm/Config.unix
+++ b/vm/Config.unix
@@ -1,5 +1,5 @@
 ifndef DEBUG
-	CFLAGS += -fomit-frame-pointer
+	SITE_CFLAGS += -fomit-frame-pointer
 endif
 
 EXE_SUFFIX =
@@ -18,7 +18,6 @@ else
 	X11_UI_LIBS = `pkg-config --libs gtk+-2.0 gtkglext-1.0`
 endif
 
-# CFLAGS += -fPIC
 FFI_TEST_CFLAGS = -fPIC
 
 # LINKER = gcc -shared -o
diff --git a/vm/Config.windows b/vm/Config.windows
index 15316932fa..0b5f843420 100755
--- a/vm/Config.windows
+++ b/vm/Config.windows
@@ -1,4 +1,4 @@
-CFLAGS += -mno-cygwin -mwindows
+SITE_CFLAGS += -mno-cygwin -mwindows
 CFLAGS_CONSOLE += -mconsole
 SHARED_FLAG = -shared
 SHARED_DLL_EXTENSION=.dll