Change conditions for installing m4 macros
Since commit a7a6449f we're checking if
sh are available in order to install m4 macro files and
This requires having an implicit dependency on m4 and sh when building GLib, even if GLib itself doesn't strictly depends on them, in order to build projects that use Autotools and depend on GLib. Without this implicit dependency, projects using Autotools won't be able to build without also rebuilding GLib.
We can leave
glib-gettextize as a dependency of
sh, after all without a shell you're likely going to end up in a very bad place when building GLib as well, but the m4 macros need to be installed unconditionally.