Change git command working directory to this project (#796)

If this project is used as subproject of another CMake project, then git commands will fail because git will be executed from wrong location.

Author: bokic

cmake/modules/Versioning.cmake

@@ -14,7 +14,7 @@ set(_VERSIONING_MODULE_DIR "${CMAKE_CURRENT_LIST_DIR}" CACHE INTERNAL "Versionin
 # Get tag (expected: v1.2.3 or 1.2.3 or 1.2.3-12-gHASH)
 execute_process(
     COMMAND git describe --tags --dirty
-    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     OUTPUT_VARIABLE GIT_DESC_RAW
     OUTPUT_STRIP_TRAILING_WHITESPACE
 )
@@ -35,12 +35,14 @@ set(PROJECT_VERSION_STRING
 # Commit hash (full + short)
 execute_process(
     COMMAND git rev-parse HEAD
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     OUTPUT_VARIABLE PROJECT_GIT_HASH
     OUTPUT_STRIP_TRAILING_WHITESPACE
 )
 
 execute_process(
     COMMAND git rev-parse --short HEAD
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     OUTPUT_VARIABLE PROJECT_GIT_HASH_SHORT
     OUTPUT_STRIP_TRAILING_WHITESPACE
 )