diff --git a/CMakeLists.txt b/CMakeLists.txt
index 98efe3892..0b196887a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,7 +31,14 @@ string(REGEX REPLACE "(..)/(..)/..(..).*" "\\1/\\2/\\3" DATE ${DATE})
 string(REGEX REPLACE "(..):(.....).*" " \\1:\\2" TIME ${TIME})
 string(CONCAT GIT_DATE_TIME ${DATE} ${TIME})
 
-execute_process(COMMAND $ENV{COMSPEC} " /C git -C ${CMAKE_CURRENT_SOURCE_DIR} rev-parse HEAD" OUTPUT_VARIABLE GIT_SHA)
+find_package(Git)
+
+if (GIT_FOUND AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git")
+    execute_process(COMMAND $ENV{COMSPEC} /C ${GIT_EXECUTABLE} -C ${CMAKE_CURRENT_SOURCE_DIR} rev-parse HEAD OUTPUT_VARIABLE GIT_SHA)
+else()
+    set(GIT_SHA 0)
+endif()
+
 string(REGEX REPLACE "[^0-9a-f]+" "" GIT_SHA ${GIT_SHA})
 
 set(BUILD_VERSION_CC ${CMAKE_CURRENT_SOURCE_DIR}/util/build_version.cc)