diff --git a/configure b/configure
index eab577d231..aad700f287 100755
--- a/configure
+++ b/configure
@@ -2505,7 +2505,7 @@ enabled stripping &&
     echo "STRIP=$strip" >> config.mak ||
     echo "STRIP=echo ignoring strip" >> config.mak
 
-echo "CPPFLAGS?=$CPPFLAGS" >> config.mak
+echo "CPPFLAGS=$CPPFLAGS" >> config.mak
 echo "CFLAGS=$CFLAGS" >> config.mak
 echo "ASFLAGS=$ASFLAGS" >> config.mak
 echo "CC_O=$CC_O" >> config.mak