--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -1730,17 +1730,19 @@ MOZ_ARG_ENABLE_BOOL(oom-breakpoint,
 if test -n "$JS_OOM_BREAKPOINT"; then
     AC_DEFINE(JS_OOM_BREAKPOINT)
 fi
 
 dnl ========================================================
 dnl = Enable using the clang plugin to build
 dnl ========================================================
 
+if test -n "$COMPILE_ENVIRONMENT"; then
 MOZ_CONFIG_CLANG_PLUGIN
+fi # COMPILE_ENVIRONMENT
 
 dnl ========================================================
 dnl = Enable static checking using sixgill
 dnl ========================================================
 
 MOZ_ARG_WITH_STRING(sixgill,
 [  --with-sixgill=path/to/sixgill
                           Enable static checking of code using sixgill],

--- a/old-configure.in
+++ b/old-configure.in
@@ -4275,17 +4275,19 @@ fi
 
 AC_SUBST_LIST(MOZ_GLUE_WRAP_LDFLAGS)
 export MOZ_GLUE_WRAP_LDFLAGS
 
 dnl ========================================================
 dnl = Enable using the clang plugin to build
 dnl ========================================================
 
+if test -n "$COMPILE_ENVIRONMENT"; then
 MOZ_CONFIG_CLANG_PLUGIN
+fi # COMPILE_ENVIRONMENT
 
 dnl ========================================================
 dnl = Enable stripping of libs & executables
 dnl ========================================================
 MOZ_ARG_ENABLE_BOOL(strip,
 [  --enable-strip          Enable stripping of libs & executables ],
     ENABLE_STRIP=1,
     ENABLE_STRIP= )