pkg-config definitions have the wrong path when the install path has spaces

[snake-4]

So, as the title says, the pkg-config files for the libraries have the wrong paths if the PothosSDR is installed in a non-default path. I get something like this in the compiler command line when the path that the PothosSDR is installed in has spaces: -IC:/Program\ Files/PothosSDR/include Files/PothosSDR/include/libhackrf which makes the compiler throw an error. Another problem is that the libosmosdr.pc and libhackrf.pc tries to add a non-existent path to the include directories in the cflags, the path is C:/build/PothosSDR_vc16/Source/libusb/libusb which I assume is the correct path on your CI servers.