Make flatpak work again

CMakeLists.txt

@@ -11,6 +11,42 @@ set(PROJECT_DATE 2023-11-24)
 math(EXPR PROJECT_VERSION_CODE 100000*${PROJECT_VERSION_MAJOR}+1000*${PROJECT_VERSION_MINOR}+${PROJECT_VERSION_PATCH})
 add_definitions( -DPROJECT_VERSION="${PROJECT_VERSION}" )
 
+# Find GIT repository data.
+if (EXISTS ${CMAKE_SOURCE_DIR}/.git)
+    # Get the current working branch
+    execute_process(
+        COMMAND git rev-parse --abbrev-ref HEAD
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        OUTPUT_VARIABLE GIT_BRANCH
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        )
+    message("Currently working with git branch ${GIT_BRANCH}")
+
+    # Get the latest abbreviated commit hash of the working branch
+    execute_process(
+        COMMAND git log -1 --format=%h
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        OUTPUT_VARIABLE GIT_COMMIT
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        )
+    message("Currently working with git Commit ${GIT_COMMIT}")
+
+    # Get the latest commit date of the working branch
+    execute_process(
+        COMMAND git log -1 --format=%as
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        OUTPUT_VARIABLE GIT_DATE
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        )
+    message("Currently working with git commit from ${GIT_DATE}")
+else()
+    message("Not working from a GIT directory")
+    set(GIT_BRANCH "")
+    set(GIT_COMMIT "")
+    set(GIT_DATE "")
+endif()
+add_compile_definitions(GIT_COMMIT="${GIT_COMMIT}")
+
 
 if(IOS)
     set(PRODUCT_BUNDLE_IDENTIFIER de.akafliegfreiburg.addhoursandminutes)