Fix mac compilation when Qt Frameworks are in use.

Qt has a special handling for mac frameworks that includes header files. Resetting QMAKE_LIBDIR_QT breaks qmake from generating proper makefile with correct include path.
Fix various other issues such as QMAKE_LFLAGS being never properly set. For the time being limit the change to mac compilation in order to minimise the risk of breaking something else elsewhere.
HD homerun compilation failed due to sig_t being previously defined in sys/signal.h

mythtv/configure

@@ -4949,6 +4949,11 @@ EOF
 
 #echo "endif # FFMPEG_CONFIG_MAK" >> $TMPMAK
 
+# Should be done on all platforms, but for the time being limit it to mac only
+if enabled darwin; then
+  echo "QMAKE_LFLAGS+=$LDFLAGS" >> $TMPMAK
+fi
+
 cp_if_changed $TMPH $MYTH_CONFIG_H
 
 if ! test -L config.h ; then

mythtv/libs/libmythhdhomerun/hdhomerun_os_posix.h

@@ -50,7 +50,10 @@
 #include <pthread.h>
 
 typedef int bool_t;
+
+#if !defined(_DARWIN_C_SOURCE)
 typedef void (*sig_t)(int);
+#endif
 
 #define LIBTYPE
 #define console_vprintf vprintf

mythtv/libs/libmythmetadata/libmythmetadata.pro

@@ -68,9 +68,6 @@ inc.files += mythuiimageresults.h metadataimagehelper.h
 INSTALLS += inc
 
 macx {
-
-    QMAKE_LFLAGS_SHLIB += -flat_namespace
-
     using_firewire:using_backend:LIBS += -F$${CONFIG_MAC_AVC} -framework AVCVideoServices
 }
 

mythtv/settings.pro

@@ -138,11 +138,12 @@ LOCAL_LIBDIR_OGL =
 }
 QMAKE_LIBDIR_OPENGL =
 
-!isEmpty( QMAKE_LIBDIR_QT ) {
-    LATE_LIBS += "-L$$QMAKE_LIBDIR_QT"
-    QMAKE_LIBDIR_QT = ""
+!macx {
+    !isEmpty( QMAKE_LIBDIR_QT ) {
+        LATE_LIBS += "-L$$QMAKE_LIBDIR_QT"
+        QMAKE_LIBDIR_QT = ""
+    }
 }
-
 EXTRA_LIBS  = $$EXTRALIBS
 
 EXTRA_LIBS += $$FREETYPE_LIBS