Remove pkg-config dependency

[4c656554]

Removing pkg-config dependency would help installation on windows. I am unsure of how feasible this is.

[emum8]

+1 I get errors when installing this package due to this dependency (that I already have)

[JohnDoe389]

+2 Same as others. Code says to check to README but there is no README info re this

Ensure pkg-config is available

try:
subprocess.check_call(['pkg-config', '--version'])
except OSError:
raise SystemExit(
"'pkg-config' is required to install this package. "
"Please see the README for details."
)