Bug 392950. fix things so that libthebes.so is rebuild when libmozcairo.a changes

configure.in

@@ -7068,7 +7068,7 @@ if test "$MOZ_SVG" -o "$MOZ_ENABLE_CANVAS" -o "$MOZ_ENABLE_CAIRO_GFX" ; then
                MOZ_CAIRO_LIBS="$MOZ_CAIRO_LIBS "'$(DEPTH)/gfx/cairo/glitz/src/mozglitz.lib $(DEPTH)/gfx/cairo/glitz/src/wgl/mozglitzwgl.lib'
            fi
        else
-           MOZ_CAIRO_LIBS='-L$(DEPTH)/gfx/cairo/cairo/src -lmozcairo -L$(DEPTH)/gfx/cairo/libpixman/src -lmozlibpixman'" $CAIRO_FT_LIBS"
+           MOZ_CAIRO_LIBS='$(DEPTH)/gfx/cairo/cairo/src/$(LIB_PREFIX)mozcairo.$(LIB_SUFFIX) $(DEPTH)/gfx/cairo/libpixman/src/$(LIB_PREFIX)mozlibpixman.$(LIB_SUFFIX)'" $CAIRO_FT_LIBS"
 
            if test "$MOZ_X11"; then
                MOZ_CAIRO_LIBS="$MOZ_CAIRO_LIBS $XLDFLAGS -lXrender -lfreetype -lfontconfig"