Index: configure.in
===================================================================
--- configure.in	(revision 266964)
+++ configure.in	(working copy)
@@ -4029,7 +4029,13 @@
       PKG_CHECK_MODULES( MOZ_NSPR, $MOZ_FLAVOUR-nspr )
     fi
 
-    if $PKG_CONFIG --exists libxul ; then
+    if test "$MOZ_FLAVOUR" != "libxul"; then
+      PKG_CHECK_MODULES( MOZILLAXPCOM, $MOZ_FLAVOUR-xpcom, HASXPCOM="TRUE", HASXPCOM="" )
+      MOZ_INC=`$PKG_CONFIG --variable=includedir $MOZ_FLAVOUR-xpcom`
+      MOZ_LIB=`$PKG_CONFIG --variable=libdir $MOZ_FLAVOUR-xpcom`
+    fi
+
+    if test -z "$HASXPCOM"; then
       PKG_CHECK_MODULES( MOZILLAXPCOM, libxul )
       MOZ_INC=`$PKG_CONFIG --variable=includedir libxul`
       MOZ_LIB=`$PKG_CONFIG --variable=libdir libxul`
@@ -4039,10 +4045,6 @@
             MOZ_LIB="$MOZ_LIB/sdk/lib"
          fi
       fi
-    else
-      PKG_CHECK_MODULES( MOZILLAXPCOM, $MOZ_FLAVOUR-xpcom )
-      MOZ_INC=`$PKG_CONFIG --variable=includedir $MOZ_FLAVOUR-xpcom`
-      MOZ_LIB=`$PKG_CONFIG --variable=libdir $MOZ_FLAVOUR-xpcom`
     fi
 
     save_CPPFLAGS="$CPPFLAGS"