The only resource I could find on what the dependencies of GLib are is here:
Compiling the GLib package
Look in the "Dependencies" section - the non-optional dependencies seem to be:
- A
iconv
function
- A
gettext
function
- A threading implementation
- The PCRE library
This means that you will need to provide (or port) each of these to whatever the target system is (e.g. a microcontroller). Although not an insurmountable barrier, a threading implementation generally implies some form of operating system.
Also its worth noting that GLib appears to depend on a "Hosted" C environment, and so you would also need to have a standard C library ported to the target environment as well (as opposed to a "Free-standing" C environment, a subset of the standard C doesn't require that a standard C library be ported). See Hosted and Free-Standing Environments. Again this generaly implies at least a very basic form of operating system.