diff --git a/nsprpub/configure b/nsprpub/configure
index 4b2f2222daa8..63609edacffb 100755
--- a/nsprpub/configure
+++ b/nsprpub/configure
@@ -5233,11 +5233,13 @@ if test -n "$_SAVE_OPTIMIZE_FLAGS"; then
 fi
 
 if test -n "$MOZ_OPTIMIZE"; then
-    OPTIMIZER=$_OPTIMIZE_FLAGS
+    CFLAGS="$CFLAGS $_OPTIMIZE_FLAGS"
+    CXXFLAGS="$CXXFLAGS $_OPTIMIZE_FLAGS"
 fi
 
 if test -n "$MOZ_DEBUG"; then
-    OPTIMIZER=$_DEBUG_FLAGS
+    CFLAGS="$CFLAGS $_DEBUG_FLAGS"
+    CXXFLAGS="$CXXFLAGS $_DEBUG_FLAGS"
 fi
 
 if test -n "$MOZ_OPTIMIZE"; then
diff --git a/nsprpub/configure.in b/nsprpub/configure.in
index 9c3c6901579d..8b22a876865c 100644
--- a/nsprpub/configure.in
+++ b/nsprpub/configure.in
@@ -2109,11 +2109,13 @@ if test -n "$_SAVE_OPTIMIZE_FLAGS"; then
 fi
 
 if test -n "$MOZ_OPTIMIZE"; then
-    OPTIMIZER=$_OPTIMIZE_FLAGS
+    CFLAGS="$CFLAGS $_OPTIMIZE_FLAGS"
+    CXXFLAGS="$CXXFLAGS $_OPTIMIZE_FLAGS"
 fi
 
 if test -n "$MOZ_DEBUG"; then
-    OPTIMIZER=$_DEBUG_FLAGS
+    CFLAGS="$CFLAGS $_DEBUG_FLAGS"
+    CXXFLAGS="$CXXFLAGS $_DEBUG_FLAGS"
 fi
 
 if test -n "$MOZ_OPTIMIZE"; then