Try to find the mfx dependency using pkg-config before falling back to manual search

[matze]

Intel Media SDK provides pkg-config information, so let's use that to find libraries and header locations. Fallback to the previous approach if that fails.

[ishmael1985]

Thanks for this PR. It should be noted that pkg-config information for Intel MSDK is already accounted for in the topic_linux_and_window branch, so if this is an issue to you, you might want to use that branch instead.

[matze]

Ah, cool, haven't seen that. Is there an ETA when this branch will be merged into master?

[ishmael1985]

Transition has been an ongoing issue since last year, but the transition should happen.

#49

The topic_linux_and_window branch is stable with even more features compared to the master branch (such as Windows support, 10-bit decode, encode, etc.). You can also get the latest stable version from my master branch here, which I would recommend - https://github.com/ishmael1985/gstreamer-media-SDK