CMake can't find GLib/GObject on Windows

[wardjk]

Building Dependencies lists Glib/GObject (http://www.gtk.org). I installed GTK+ using MSYS2 on Windows 10.
My paths:
GStreamer: C:\gstreamer
GTK: C:\Programs\gtk\gtk-3.19
qt-gstreamer: C:\Programs\qt-gstreamer

During build, CMake reported

Could NOT find GLIB2 (missing: GLIB2_LIBRARIES GLIB2_MAIN_INCLUDE_DIR)
Could NOT find GObject (missing: GOBJECT_INCLUDE_DIR GOBJECT_LIBRARIES)

I might not have the necessary environment variables or paths that must be defined. I don't know if they were supposed to be created during installation or if I'm supposed to create or define them.

The file C:\Programs\qt-gstreamer\cmake\modules\FindGLIB2.cmake contains

find_path(GLIB2_MAIN_INCLUDE_DIR glib.h
PATH_SUFFIXES glib-2.0
HINTS ${PKG_GLIB_INCLUDE_DIRS} ${PKG_GLIB_INCLUDEDIR})

so to the environment variable "PKG_CONFIG_PATH" I added "C:\Programs\gtk\gtk-3.19\include" because glib.h is in "C:\Programs\gtk\gtk-3.19\include\glib-2.0".
Something I found that doesn't seem right is in C:\Programs\gtk\gtk-3.19\lib\pkgconfig\glib-2.0.pc which contains

prefix=/opt
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

which makes this appear to be for linux, not Windows.
What seems to be more appropriate is what I found in C:\gstreamer\1.0\x86\lib\pkgconfig\glib-2.0.pc which contains

prefix=/c/gstreamer/1.0/x86
exec_prefix=${prefix}
libdir=/c/gstreamer/1.0/x86/lib
includedir=${prefix}/include

but when I replaced the previous path with "C:\gstreamer\1.0\x86\lib\pkgconfig" in "PKG_CONFIG_PATH", this didn't change the symptoms.
If you could let me know what I might be missing that would let cmake know where to find GLib/GObject, I'd greatly appreciate it.

[detrout]

So at the worst case you could try using one of the CMake guis to try and manually set the paths.

Could you check your environment? I thought I'd seen a something that there might be some environment variables pointing to where the pkgconfig directories are? or even better is there a variable pointing to the gtk-3.19 dir?

The gstreamer .pc file does definitely look more correct for windows than the gtk file.

I don't have a windows machine so I can't help much. But I can try to help puzzle it out with you. (Ideally would be to get to a pull request)

[wardjk]

While grasping for straws, I tried CMake GUI but the paths I tried evidently weren't sufficient. I don't even know if the glib-2.0.pc files I found are useable as-is but they are what were installed. I was expecting environment variables to have already been set by the installers but because the right variables may not even be present, I don't know what's missing. I was hoping someone would be able to spot which variables are required and where they should point. I've tried adding multiple combinations but nothing has worked yet. It seems that if anyone else had tried installing the required components on Windows 10, they would have run into the same build problems too. Maybe Windows isn't letting the installers do their job completely but there weren't any complaints from the installers.

[detrout]

Got distracted....

The gstreamer glib config file looks more like its using windows confentions... though possibly like it was built under cygwin?

Is there a pkg-config command? does pkg-config --cflags glib-2.0 return anything? or just errors out?

[wardjk]

An ugly workaround I used to get CMake to find GLib & GObject was to change the linuxy prefix path from "/c/gstreamer/1.0/x86" to "C:\gstreamer\1.0\x86". I only had to edit glib-2.0.pc and none of the other 99 .pc files in the same directory. It seems that the prefix could/should be set with an environment variable but whatever variable it may take, I didn't have it. The installation was for Windows but these files weren't compatible out of the box.