modules/basic/basic-win32.c: Silence a Warning

The length is an unsigned int, and it is already enforced that it must
be greater or equal to 0 in this source file, so fix the type declaration.
[git.mk] Update
Fix build --withincluded-modules

According to Doug Felt:

pango's configure dies with --with-included-modules=yes, because when
have_libthai is true, thai_modules ends up being ",thai-lang", and
all_modules (and included_modules) ends up containing ',,'.

for module in $included_modules;

ends up with module='' and the case $module falls back to default, which
calls as_fn_error.
Bug 720379 - SIGFPE in pango_layout_iter_get_char_extents()

Untested.