--- Makefile.in
+++ Makefile.in
@@ -252,8 +252,8 @@
 BUILD_CFLAGS = @BUILD_CFLAGS@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
-CFLAGS = @CFLAGS@
-CPPFLAGS = @CPPFLAGS@
+CFLAGS = $(patsubst -Ofast,-O2, @CFLAGS@)
+CPPFLAGS = $(patsubst -Ofast,-O2, @CPPFLAGS@)
 CSCOPE = @CSCOPE@
 CTAGS = @CTAGS@
 CYGPATH_W = @CYGPATH_W@