Look for -uninstalled pc files and update PKG_CONFIG_PATH with the
directories containing those.
This feature is useful for users building the GStreamer stack
using meson and having to link it to another project which is still
using the autotools.
Fix a regression from the old gst-uninstalled tool.
https://bugzilla.gnome.org/show_bug.cgi?id=776810
This environment is meant to be setup in a Visual Studio
'Native X64 tools' terminal, and takes for granted that
msys2 has been installed, Visual Studio has C(++) support
has been installed and python3 is installed and is present
in PATH.
https://bugzilla.gnome.org/show_bug.cgi?id=775281
subprocess.call runs programs directly when shell=False and can't
take advantage of the association that makes python scripts
executable in shells, so explicitly add the interpreter to the
args for call.
Run the windows command prompt by default in gst-uninstalled.
