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, 9 insertions, 0 deletions

diff --git a/giscanner/pkgconfig.py b/giscanner/pkgconfig.py
index 6f0b2d57..66822378 100644
--- a/giscanner/pkgconfig.py
+++ b/giscanner/pkgconfig.py
@@ -56,3 +56,12 @@ def libs(packages, msvc_syntax=False, ignore_errors=True, command=None):
     flags.extend(packages)
     out = check_output(flags, ignore_errors, command)
     return shlex.split(out)
+
+
+def bindir(packages, ignore_errors=True, command=None):
+    flags = []
+    flags.append('--variable')
+    flags.append('bindir')
+    flags.extend(packages)
+    out = check_output(flags, ignore_errors, command)
+    return shlex.split(out)