make sure that git repo info is only added if the musrfit project source is indeed a git repo, and not e.g. a download.

src/musredit_qt6/musredit/CMakeLists.txt

@@ -1,5 +1,12 @@
 #--- musredit for Qt > 6.0 ----------------------------------------------------
 
+#--- check if project source is repo ------------------------------------------
+if (IS_GIT_REPO)
+  set(HAVE_GIT_REV_H "-DHAVE_GIT_REV_H")  
+else (IS_GIT_REPO)
+  set(HAVE_GIT_REV_H "")  
+endif (IS_GIT_REPO)
+
 set(qt_libs Qt6::Core Qt6::Widgets Qt6::Network Qt6::Xml Qt6::Svg Qt6::PrintSupport)
 
 set(musredit_src
@@ -115,6 +122,11 @@ target_include_directories(musredit
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../../include>
 )
 
+target_compile_options(musredit
+  PRIVATE
+    "${HAVE_GIT_REV_H}"  
+)
+
 target_link_libraries(musredit ${qt_libs})
 
 #--- installation info --------------------------------------------------------