pidgin/pidgin

Make it possible so that libpurple plugins can use functions defined in libpurple/glibcompat.h

Testing Done:
Compiled on linux and raspberry pi os which fixes that build.

Reviewed at https://reviews.imfreedom.org/r/169/
foreach prog : ['caps', 'digest_md5', 'scram', 'jutil']
e = executable(
'test_jabber_' + prog, 'test_jabber_@0@.c'.format(prog),
link_with : [jabber_prpl],
dependencies : [libxml, libpurple_dep, libsoup, glib])
test('jabber_' + prog, e)
endforeach