Don't do git.

Index: cmake/AddVersionCompileDefinition.cmake
--- cmake/AddVersionCompileDefinition.cmake.orig
+++ cmake/AddVersionCompileDefinition.cmake
@@ -3,40 +3,6 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 function(add_version_compile_definition versionstr_file versionstr_def)
-	find_package(Git QUIET)
-	if(Git_FOUND)
-		# Find git repository
-		execute_process(
-			COMMAND ${GIT_EXECUTABLE} rev-parse --absolute-git-dir
-			WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-			RESULT_VARIABLE git_dir_result
-			OUTPUT_VARIABLE git_dir
-			ERROR_QUIET
-			OUTPUT_STRIP_TRAILING_WHITESPACE
-		)
-
-		if (git_dir_result EQUAL 0)
-			# Find version number from git
-			execute_process(
-				COMMAND ${GIT_EXECUTABLE} describe --tags --match "v*"
-				WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-				OUTPUT_VARIABLE versionstr
-				ERROR_QUIET
-				OUTPUT_STRIP_TRAILING_WHITESPACE
-			)
-			string(REGEX REPLACE "^v" "" versionstr "${versionstr}")
-
-			# Rerun CMake when git repository changes
-			if (EXISTS ${git_dir}/logs/HEAD)
-				set_property(
-					DIRECTORY
-					APPEND
-					PROPERTY CMAKE_CONFIGURE_DEPENDS ${git_dir}/logs/HEAD
-				)
-			endif()
-		endif()
-	endif()
-
 	# Fall back to project's VERSION
 	if ("${versionstr}" STREQUAL "")
 		set(versionstr ${PROJECT_VERSION})
