diff --git a/libretro-build.sh b/libretro-build.sh
index aee4e186..a844ee36 100755
--- a/libretro-build.sh
+++ b/libretro-build.sh
@@ -163,6 +163,13 @@ mkdir -p "$RARCH_DIST_DIR"
 if [ $1 ]; then
    $1
 else
+if [ -z $BUILD_LIBRETRO_GL ]; then
+   build_libretro_modelviewer
+   build_libretro_scenewalker
+if [ -z $BUILD_EXPERIMENTAL ]; then
+   build_libretro_mupen64
+fi
+fi
    build_libretro_bsnes
    build_libretro_mednafen
    build_libretro_mednafen_gba
diff --git a/libretro-config.sh b/libretro-config.sh
index 1dcf4204..14be975c 100755
--- a/libretro-config.sh
+++ b/libretro-config.sh
@@ -1,7 +1,17 @@
 #!/bin/sh
 
+if [ -f "libretro-config-user.sh" ]; then
+# All your user defines (listed below) should go in this local file
+. ./libretro-config-user.sh
+fi
+
+#User defines (should be defined in local libretro-config-user.sh file)
+
 #if uncommented, will fetch repos with read+write access. Useful for committers
 #export WRITERIGHTS
 
 #if uncommented, will build libretro GL cores as well. Doesn't need to be defined for mobile platforms
 #export BUILD_LIBRETRO_GL
+
+#if uncommented, will build experimental cores as well which are not yet fit for release.
+#export BUILD_EXPERIMENTAL