cmake: in macro generate_compiler_warning_flags prevent duplicates in variable contai...

Signed-off-by: Ralf Habacker <ralf.habacker@freenet.de>

diff --git a/cmake/modules/Macros.cmake b/cmake/modules/Macros.cmake
index c3c057e6f48a89361abcda48763ab00130e8ae8c..f581508ff206dd22c902df98f295ad5e7b0b4666 100644 (file)
--- a/cmake/modules/Macros.cmake
+++ b/cmake/modules/Macros.cmake
@@ -157,6 +157,7 @@ macro(generate_compiler_warning_flags)
     unset(USED)
     unset(USED_WARNINGS)
     unset(USED_DISABLED)
+    unset(USED_UNSUPPORTED)
 
     if(MSVC)
         # level 1 is default
@@ -175,7 +176,7 @@ macro(generate_compiler_warning_flags)
         if(_flag_supported)
             set(temp "${temp} ${error_prefix}${warning}")
             list(APPEND USED ${warning})
-        else()
+        elseif(NOT warning IN_LIST USED_UNSUPPORTED)
             list(APPEND USED_UNSUPPORTED ${warning})
         endif()
     endforeach()
@@ -191,7 +192,7 @@ macro(generate_compiler_warning_flags)
                 set(temp "${temp} ${enabled_prefix}${warning}")
                 list(APPEND USED_WARNINGS ${warning})
                 list(APPEND USED ${warning})
-            else()
+            elseif(NOT warning IN_LIST USED_UNSUPPORTED)
                 list(APPEND USED_UNSUPPORTED ${warning})
             endif()
         endif()
@@ -208,7 +209,7 @@ macro(generate_compiler_warning_flags)
                 set(temp "${temp} ${disabled_prefix}${warning}")
                 list(APPEND USED_DISABLED ${warning})
                 list(APPEND USED ${warning})
-            else()
+            elseif(NOT warning IN_LIST USED_UNSUPPORTED)
                 list(APPEND USED_UNSUPPORTED ${warning})
             endif()
         endif()