Have dolphin_scmrev run ScmRevGen from CMAKE_CURRENT_SOURCE_DIR

[JesseTG]

This is another little fix to simplify FetchContent'ing Dolphin. Without this PR, the dolphin_scmrev target will try to use a file named ScmRevGen.cmake in the including project's CMake directory.

[AdmiralCurtiss]

Makes sense. There's a few other instances of CMAKE_SOURCE_DIR that probably want to execute relative to the current directory instead of relative of the top-level CMake file, too, such as

dolphin/CMakeLists.txt

Lines 158 to 160 in acb18a5

	list(APPEND CMAKE_MODULE_PATH
	${CMAKE_SOURCE_DIR}/CMake
	)

[JesseTG]

Makes sense. There's a few other instances of CMAKE_SOURCE_DIR that probably want to execute relative to the current directory instead of relative of the top-level CMake file, too, such as

dolphin/CMakeLists.txt

Lines 158 to 160 in acb18a5

	list(APPEND CMAKE_MODULE_PATH
	${CMAKE_SOURCE_DIR}/CMake
	)

Sure, I can knock 'em out for you if you'd like. I'll comb through myself, but are there any instances you'd like to highlight?

[JesseTG]

@AdmiralCurtiss How's this?

[AdmiralCurtiss]

Err, appreciated but I don't think that's correct. CMAKE_CURRENT_SOURCE_DIR gives you directory of the currently running CMakeLists.txt, so for most of these you have to go up a few levels in order to end up at the same relative location, eg.:

[AdmiralCurtiss]

I'm guessing you will be back but yeah sure this is fine.

[JesseTG]

I'm guessing you will be back but yeah sure this is fine.

Yes, this is a safe bet. Thanks for merging this. 👍