Remove use of LINGUAS file to prevent writes to the source directory

This is for the resolution of bug 3133

Signed-off-by: aneejit1 <aneejit1@gmail.com>

modules/TDEMacros.cmake

@@ -1918,9 +1918,13 @@ macro( tde_create_translated_desktop )
 
     if( DESKTOP_MERGE_MSGFMT )
 
-      # create LINGUAS file for msgfmt
-      string( REPLACE ".po;" "\n" _linguas "${_translations};" )
-      file( WRITE ${_po_dir}/LINGUAS "${_linguas}" )
+      # Decide which translations to build; the ones selected in the
+      # LINGUAS environment variable, or all that are available.
+      if( DEFINED ENV{LINGUAS} )
+        set( _linguas "$ENV{LINGUAS}" )
+      else( )
+        string( REPLACE ".po;" " " _linguas "${_translations};" )
+      endif( )
 
       # prepare keywords for msgfmt
       set( _keywords_arg "--keyword=" )
@@ -1932,22 +1936,10 @@ macro( tde_create_translated_desktop )
       get_filename_component( _src ${_src} ABSOLUTE )
       add_custom_command(
         OUTPUT ${_basename}
-        COMMAND ${MSGFMT_EXECUTABLE} --desktop --template ${_src} -d ${_po_dir} -o ${_basename} ${_keywords_arg}
+        COMMAND ${CMAKE_COMMAND} -E env "LINGUAS=${_linguas}" ${MSGFMT_EXECUTABLE} --desktop --template ${_src} -d ${_po_dir} -o ${_basename} ${_keywords_arg}
         DEPENDS ${_src}
       )
 
-      # cleanup LINGUAS file
-      get_filename_component( _linguas_path "${_po_dir}/LINGUAS" ABSOLUTE )
-      file( RELATIVE_PATH _linguas_path "${CMAKE_SOURCE_DIR}" "${_linguas_path}" )
-      string( REPLACE "/" "+" _linguas_cleanup_target "${_linguas_path}-cleanup" )
-      if( NOT TARGET ${_linguas_cleanup_target} )
-        add_custom_target( ${_linguas_cleanup_target} ALL
-          COMMAND ${CMAKE_COMMAND} -E remove ${_po_dir}/LINGUAS
-          COMMENT "Cleanup ${_linguas_path} file..."
-        )
-      endif( )
-      add_dependencies( ${_linguas_cleanup_target} "${_target}" )
-
     else( )
 
       # create template for intltool-merge