QNX: Enable pre-compiled header support for QNX

Change-Id: I6af69965b19c5d0d7a46de8000433bc5f1f2abcb
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thomas McGuire <thomas.mcguire@kdab.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

config.tests/unix/precomp.test

@@ -27,7 +27,7 @@ EOF
     rm -f header.pchi header.o source.o
     ;;
 
-*g++*|c++)
+*g++*|c++|*qcc*)
     case `"$COMPILER" -dumpversion 2>/dev/null` in
     3.*)
         ;;

mkspecs/common/qcc-base.conf

@@ -42,6 +42,11 @@ QMAKE_CXXFLAGS_APP        += $$QMAKE_CFLAGS_APP
 QMAKE_CXXFLAGS_YACC       += $$QMAKE_CFLAGS_YACC
 QMAKE_CXXFLAGS_HIDESYMS   += $$QMAKE_CFLAGS_HIDESYMS -fvisibility-inlines-hidden
 
+QMAKE_CFLAGS_PRECOMPILE       = -x c-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
+QMAKE_CFLAGS_USE_PRECOMPILE   = -Wc,-include -Wc,${QMAKE_PCH_OUTPUT_BASE}
+QMAKE_CXXFLAGS_PRECOMPILE     = -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
+QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE
+
 QMAKE_LFLAGS         += -lang-c++
 QMAKE_LFLAGS_DEBUG   += -lang-c++
 QMAKE_LFLAGS_APP     += -lang-c++