Don't use a variable name that might be used in other files.

myDir is also used in the Grantlee config file, so if Grantlee
was found, this call failed.

Modules/GenerateExportHeader.cmake

@@ -215,7 +215,7 @@ macro(_test_compiler_has_deprecated)
   endif()
 endmacro()
 
-set(myDir "${CMAKE_CURRENT_LIST_DIR}")
+get_filename_component(_GENERATE_EXPORT_HEADER_MODULE_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)
 
 macro(_DO_SET_MACRO_VALUES TARGET_LIBRARY)
   set(DEFINE_DEPRECATED)
@@ -308,7 +308,7 @@ macro(_DO_GENERATE_EXPORT_HEADER TARGET_LIBRARY)
     set(EXPORT_IMPORT_CONDITION ${TARGET_LIBRARY}_EXPORTS)
   endif()
 
-  configure_file("${myDir}/exportheader.cmake.in" "${EXPORT_FILE_NAME}" @ONLY)
+  configure_file("${_GENERATE_EXPORT_HEADER_MODULE_DIR}/exportheader.cmake.in" "${EXPORT_FILE_NAME}" @ONLY)
 endmacro()
 
 function(GENERATE_EXPORT_HEADER TARGET_LIBRARY)
@@ -343,4 +343,4 @@ function(add_compiler_export_flags)
     set (EXTRA_FLAGS "${EXTRA_FLAGS} -fvisibility-inlines-hidden")
   endif()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${EXTRA_FLAGS}" PARENT_SCOPE)
-endfunction()
+endfunction()