--- a/configure
+++ b/configure
@@ -152,12 +152,12 @@ rm -f pngquant-gcccheck pngquant-gcccheck.c
 status "Compiler" "$CC"
 
 # init flags
-CFLAGS=${CFLAGS:--fno-math-errno -funroll-loops -fomit-frame-pointer -Wall}
+CFLAGS=${CFLAGS:--fno-math-errno -funroll-loops -fomit-frame-pointer}
 cflags "-std=c99 -I."
 
 # DEBUG
 if [ -z "$DEBUG" ]; then
-    cflags "-O3 -DNDEBUG"
+    cflags "-DNDEBUG"
     status "Debug" "no"
 else
     cflags "-O1 -g"