common: Use PROJECT_SOURCE_DIR to find CMakeModules

Fixes CMake configuration when yuzu is a submodule of another project.

src/common/CMakeLists.txt

@@ -16,7 +16,7 @@ find_package(Git QUIET)
 
 add_custom_command(OUTPUT scm_rev.cpp
     COMMAND ${CMAKE_COMMAND}
-      -DSRC_DIR=${CMAKE_SOURCE_DIR}
+      -DSRC_DIR=${PROJECT_SOURCE_DIR}
       -DBUILD_REPOSITORY=${BUILD_REPOSITORY}
       -DTITLE_BAR_FORMAT_IDLE=${TITLE_BAR_FORMAT_IDLE}
       -DTITLE_BAR_FORMAT_RUNNING=${TITLE_BAR_FORMAT_RUNNING}
@@ -28,13 +28,13 @@ add_custom_command(OUTPUT scm_rev.cpp
       -DGIT_BRANCH=${GIT_BRANCH}
       -DBUILD_FULLNAME=${BUILD_FULLNAME}
       -DGIT_EXECUTABLE=${GIT_EXECUTABLE}
-      -P ${CMAKE_SOURCE_DIR}/CMakeModules/GenerateSCMRev.cmake
+      -P ${PROJECT_SOURCE_DIR}/CMakeModules/GenerateSCMRev.cmake
     DEPENDS
       # Check that the scm_rev files haven't changed
       "${CMAKE_CURRENT_SOURCE_DIR}/scm_rev.cpp.in"
       "${CMAKE_CURRENT_SOURCE_DIR}/scm_rev.h"
       # technically we should regenerate if the git version changed, but its not worth the effort imo
-      "${CMAKE_SOURCE_DIR}/CMakeModules/GenerateSCMRev.cmake"
+      "${PROJECT_SOURCE_DIR}/CMakeModules/GenerateSCMRev.cmake"
     VERBATIM
 )