Windows: Fix building and running on Python 3.8+

Python 3.8.x and later changed the way how dependent DLLs can be found for a
given Python module that depends on the presence of external, non-system DLLs,
for more fine-grained DLLs searching and loading, as well as for security
purposes, which required the use of os.add_dll_directory().

Thus, the scripts in scanner/ must be updated such that:

-We are able to find and load the GObject and GLib DLLs, at least, on
 initialization, via the use of 'pkg-config --variable bindir', as we already
 depend on the GLib DLLs.   Note that since the gobject-2.0.pc file does not
 have a 'bindir' entry, we use gio-2.0.pc instead to discover the bindir of the
 GObject and GLib DLLs.  Likewise, we use the same technique for pkg-config
 files that are dependent upon when using g-ir-scanner (or friends) on items
 that are higher up in the stack.

-We are able to find any other DLLs (e.g. non-GNOME DLLs such as ZLib) that
 are dependent but are not found in the path(s) given by 'pkg-config --variable
 bindir' with the envvar GI_EXTRA_BASE_DLL_DIRS, as needed.  Note that
 GI_EXTRA_BASE_DLL_DIRS can be multiple paths, and that the results from
 'pkg-config --variable bindir' takes precendence, in a LIFO manner.

1 files changed, 4 insertions, 0 deletions

diff --git a/tools/g-ir-tool-template.in b/tools/g-ir-tool-template.in
index 8462f88a..c4a10a28 100755
--- a/tools/g-ir-tool-template.in
+++ b/tools/g-ir-tool-template.in
@@ -96,5 +96,9 @@ if not os.path.isfile(os.path.join(pylibdir, 'giscanner', '_giscanner' + py_mod_
 
 sys.path.insert(0, pylibdir)
 
+from giscanner.utils import dll_dirs
+dll_dirs = dll_dirs()
+dll_dirs.add_dll_dirs(['gio-2.0'])
+
 from giscanner.@TOOL_MODULE@ import @TOOL_FUNCTION@
 sys.exit(@TOOL_FUNCTION@(sys.argv))