Convert all xbps-base-chroot pkgs to subpkgs.

Also introduce "libs.depends", that adds a rundep of a package
with a proper version. This is to avoid modifying all dependent
packages if there's an API/ABI change.

--HG--
extra : convert_revision : a46b11b8e9187bdb2bfc954ad5ff40ecd9c0fe31

templates/gzip/template

@@ -1,5 +1,6 @@
 # Template file for 'gzip'
 pkgname=gzip
+sourcepkg=gzip
 version=1.3.12
 distfiles="http://ftp.gnu.org/gnu/gzip/$pkgname-$version.tar.gz"
 build_style=gnu_configure
@@ -13,4 +14,4 @@ long_desc="
  standard compression program for its system."
 
 base_chroot=yes
-run_depends="glibc-2.8"
+subpackages="base docs"