With the way the runtime checks are currently set up, every single
openh264 release, no matter how minor, is considered an ABI break and
requires ffmpeg recompilation. This is unnecessarily strict because it
doesn't allow downstream distributions to ship any openh264 bug fix
version updates without breaking ffmpeg's openh264 support.

Years ago, at the time when ffmpeg's openh264 support was merged,
openh264 releases were done without a versioned soname (the library was
just libopenh264.so, unversioned). Since then, starting with version
1.3.0, openh264 has started using versioned sonames and the intent has
been to bump the soname every time there's a new release with an ABI
change.

This patch drops the exact version check and instead adds a minimum
requirement on 1.3.0 to the configure script.
Signed-off-by: Kalev Lember <klember@redhat.com>
Signed-off-by: Martin Storsjö <martin@martin.st>