libs: glib2: fix provided pkg-config and always use host tools

libs: glib2: fix provided pkg-config and always use host tools

For the InstallDev target, the pkg-config should point to the glib2 host
tools for glib_compile_resources, gdbus_codegen, glib_genmarshal and
glib_mkenums instead of pointing to the targets ones as they are
unusable by the host machine (due to crosscompiling)

Fix the pkg-config to reference the host tools by replaying the entry
and use the prefix_hostpkg variable provided by our pkg-config.

Link: https://github.com/openwrt/packages/pull/23881
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>