Hack extconf for RHEL env
Merge pull request #2 from jgrevich/dev

Hack extconf for RHEL env
Update xmlsec to use SHA256 by default for realz.
Merge pull request #3 from omb-awong/use_sha256

Update xmlsec to use SHA256 by default for realz.
Ensure -L from pkg-config paths are also in build.
Use the official pkgconfig command.

Much cleaner. Thanks @jgrevich!