vala: don't modify the pkg-config file

Some packages, namely 'libsoup' fail to build with the changes, instead
wrap vapigen-0.42

srcpkgs/vala/template

@@ -1,7 +1,7 @@
 # Template file for 'vala'
 pkgname=vala
 version=0.42.5
-revision=2
+revision=3
 build_style=gnu-configure
 configure_args="--disable-graphviz"
 hostmakedepends="flex libxslt pkg-config automake libtool"
@@ -28,18 +28,6 @@ pre_configure() {
 	autoreconf -fi
 }
 
-post_install() {
-	# Prefix the variables 'datadir' 'vapidir' and 'vapidir_versioned'
-	# with pc_sysrootdir so it gets expanded to the value of
-	# PKG_CONFIG_SYSROOT_DIR, this is necessary for packages that
-	# query pkg-config for the variables as we need to return the
-	# values from the cross environment not the native one.
-	vsed -e 's|^datadir=.*|datadir=${pc_sysrootdir}/${datarootdir}|g' \
-		 -e 's|^vapidir=.*|vapidir=${pc_sysrootdir}/${datadir}/vala/vapi|g' \
-		 -e 's|^vapidir_versioned=.*|vapidir_versioned=${pc_sysrootdir}/${datadir}/vala-0.42/vapi|g' \
-		 -i ${DESTDIR}/usr/lib/pkgconfig/vapigen-0.42.pc
-}
-
 libvala_package() {
 	short_desc+=" - shared library"
 	pkg_install() {