Creation of Info.plist files through Xcode is more canonical and
future-proof, as it will automatically pick up changes/updates
introduced by Apple. Non-standard keys can still be added via a
template file, which will then be extended by Xcode with the default
keys.
clang expects an empty prototype to explicitly use `void`.
Also silences the warning in `libobs-opengl`, `obsglad`, `caption`,
`mac-syphon` and `obs-x264-test`.
Switching to a static library that contains version information as
const char strings has multiple benefits:
* The version information provided externally via compiler definitions
will fail compilation early if malformed
* An updated version string (which will happen with every commit) will
not invalidate existing compilation units, because only the static
library is affected by the change
* An update of the version change just requires a recompilation of the
static library and a linker update
* An update of the version will _not_ infect the rest of the codebase
(as it does currently, because everything includes obsconfig.h one
way or another)
* Other modules which used the macro definition directly have been
updated as much as possible to use the proper getter method from
`libobs` instead (some Windows-specific modules use preprocessor
string composition, the value has been added as a compiler definition
directly in those cases)
* Because the impact of a version change due to a commit hash change
is limited to the static library, ccache hit rates should be
improved considerably
