CMAKE help if cwd not git dir

Hi all,

please consider applying the patch below. The git is called in some
different directory and that is why fails. I'm not sure why it was
called in different directory, maybe because I build libwebsockets
with CMake's ExternalProject.

Best,
Arokux

Signed-off-by: Arokux X <arokux@gmail.com>

CMakeLists.txt

@@ -23,6 +23,7 @@ message(STATUS "CMAKE_TOOLCHAIN_FILE='${CMAKE_TOOLCHAIN_FILE}'")
 find_package(Git)
 if(GIT_EXECUTABLE)
 	execute_process(
+    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
     COMMAND "${GIT_EXECUTABLE}" log -n 1 --pretty=%h
     OUTPUT_VARIABLE GIT_HASH
     OUTPUT_STRIP_TRAILING_WHITESPACE