zlib 1.2.5: install pkgconfig file, needed for e.g. modern webkit

Upstream has grown cmake support which would allow us to dump the OE autotools hack, but the cmakefile doesn't install the .pc file either and breaks with zlib-native

(From OE-Core rev: e1312eef88cb0f3f1557d431f0b31520b2a9968e)

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/zlib/zlib_1.2.5.bb

@@ -7,12 +7,12 @@ LICENSE = "Zlib"
 LIC_FILES_CHKSUM = "file://zlib.h;beginline=4;endline=23;md5=084e9c30e4e6272c3b057b13c6467f3d"
 
 DEPENDS = "libtool-cross"
-PR = "r1"
+PR = "r3"
 
 SRC_URI = "http://www.zlib.net/${BPN}-${PV}.tar.bz2 \
            file://configure.ac \
            file://Makefile.am \
-	   file://fix.inverted.LFS.logic.patch"
+           file://fix.inverted.LFS.logic.patch"
 
 SRC_URI[md5sum] = "be1e89810e66150f5b0327984d8625a0"
 SRC_URI[sha256sum] = "239aead2f22f16bfcfa6a6a5150dcbd6d6f2e4d1eaa8727b5769ea014120b307"
@@ -24,4 +24,18 @@ do_configure_prepend () {
 	cp ${WORKDIR}/Makefile.am ${S}/
 }
 
+do_install_append () {
+	sed \
+		-e 's:@prefix@:${prefix}:' \
+		-e 's:@exec_prefix@:${exec_prefix}:' \
+		-e 's:@libdir@:${libdir}:' \
+		-e 's:@sharedlibdir@:${libdir}:' \
+		-e 's:@includedir@:${includedir}:' \
+		-e 's:@VERSION@:${PV}:' \
+		zlib.pc.in > zlib.pc
+
+	install -d ${D}${libdir}/pkgconfig
+	install -m 0644 zlib.pc ${D}${libdir}/pkgconfig/
+}
+
 BBCLASSEXTEND = "native nativesdk"