xz: Use relative paths in pkg-config metadata file

By default, the liblzma pkg-config file (liblzma.pc) is generated with
absolute paths, which $(STAGING_DIR_HOST)/bin/pkg-config is unable to
override.

This patches the file to use paths relative to ${prefix} and
${exec_prefix}.

Signed-off-by: Jeffery To <jeffery.to@gmail.com>

utils/xz/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=xz
 PKG_VERSION:=5.2.4
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=@SF/lzmautils

utils/xz/patches/001-relative-pkg-config-paths.patch

@@ -0,0 +1,13 @@
+--- a/src/liblzma/liblzma.pc.in
++++ b/src/liblzma/liblzma.pc.in
+@@ -7,8 +7,8 @@
+ 
+ prefix=@prefix@
+ exec_prefix=@exec_prefix@
+-libdir=@libdir@
+-includedir=@includedir@
++libdir=${exec_prefix}/lib
++includedir=${prefix}/include
+ 
+ Name: liblzma
+ Description: General purpose data compression library