diff --git a/mkspecs/features/mac/objective_c.prf b/mkspecs/features/mac/objective_c.prf
index b3b1d4be998..ed1ad8ad384 100644
--- a/mkspecs/features/mac/objective_c.prf
+++ b/mkspecs/features/mac/objective_c.prf
@@ -1,6 +1,7 @@
 
 # Objective-C/C++ sources go in SOURCES, like all other sources
 SOURCES += $$OBJECTIVE_SOURCES
+unset(OBJECTIVE_SOURCES)
 
 # Strip C/C++ flags from QMAKE_OBJECTIVE_CFLAGS just in case
 QMAKE_OBJECTIVE_CFLAGS -= $$QMAKE_CFLAGS $$QMAKE_CXXFLAGS
@@ -8,3 +9,4 @@ QMAKE_OBJECTIVE_CFLAGS -= $$QMAKE_CFLAGS $$QMAKE_CXXFLAGS
 # Add Objective-C/C++ flags to C/C++ flags, the compiler can handle it
 QMAKE_CFLAGS += $$QMAKE_OBJECTIVE_CFLAGS
 QMAKE_CXXFLAGS += $$QMAKE_OBJECTIVE_CFLAGS
+unset(QMAKE_OBJECTIVE_CFLAGS)