--- a/configure.in
+++ b/configure.in
@@ -5168,18 +5168,18 @@ MOZ_ARG_WITH_STRING(branding,
 [  --with-branding=dir    Use branding from the specified directory.],
     MOZ_BRANDING_DIRECTORY=$withval)
 
 REAL_BRANDING_DIRECTORY="${MOZ_BRANDING_DIRECTORY}"
 if test -z "$REAL_BRANDING_DIRECTORY"; then
   REAL_BRANDING_DIRECTORY=${MOZ_BUILD_APP}/branding/nightly
 fi
 
-if test -f "$topsrcdir/$REAL_BRANDING_DIRECTORY/configure.sh"; then
-  . "$topsrcdir/$REAL_BRANDING_DIRECTORY/configure.sh"
+if test -f "${_topsrcdir}/$REAL_BRANDING_DIRECTORY/configure.sh"; then
+  . "${_topsrcdir}/$REAL_BRANDING_DIRECTORY/configure.sh"
 fi
 
 AC_SUBST(MOZ_BRANDING_DIRECTORY)
 
 dnl ========================================================
 dnl = Distribution ID
 dnl ========================================================
 MOZ_ARG_WITH_STRING(distribution-id,