pango: fix host build

pango likes to rerun it's configure script at make time, and it then
fails to find the correct pkg-config files (it finds the ones ins
STAGING_DIR) causing problems if they are not compatible.

Fix it by setting PKG_CONFIG_PATH in it's make environment.

package/pango/pango.mk

@@ -88,7 +88,7 @@ $(STAMP_DIR)/host_pango_configured: $(STAMP_DIR)/host_pango_unpacked $(STAMP_DIR
 	touch $@
 
 $(STAMP_DIR)/host_pango_compiled: $(STAMP_DIR)/host_pango_configured
-	$(HOST_MAKE_ENV) $(MAKE) -C $(PANGO_HOST_DIR)
+	$(HOST_MAKE_ENV) PKG_CONFIG_PATH="$(HOST_DIR)/usr/lib/pkgconfig$(PKG_CONFIG_PATH)" $(MAKE) -C $(PANGO_HOST_DIR)
 	touch $@
 
 $(STAMP_DIR)/host_pango_installed: $(STAMP_DIR)/host_pango_compiled