Support minimum version

[kylemayes]

Support minimum version

[KyleMayes]

Implemented as the assert-minimum Cargo feature in v0.27.0.

[KyleMayes]

Do you mean something like if clang-sys is a dependency with the features clang_6_0 and minimum_version (or another name) and a libclang library with a version in the filename not greater than or equal to the requested version (e.g., libclang-6.so or libclang.7.0.so) cannot be found, an error will be thrown?

The only alternative I can think of that doesn't use the filename to check the version would be to link to each libclang library in the build script using libloading and attempting to load a function only present on versions of libclang greater than or equal to the requested version.