[osx] Clean up Makefile.am

The OS X backend Makefile.am was missing a line concatenation, and
so the -xobjective-c directive was always ignored.

Instead of dumping everything into INCLUDES and LDADD we should follow
what the rest of the backends do, and use per-target CFLAGS and LDADD,
and reserve the INCLUDES to -D and -I directives.

Thanks to: Christian Hergert <chris@dronelabs.com>

clutter/osx/Makefile.am

@@ -2,24 +2,22 @@ libclutterincludedir = $(includedir)/clutter-@CLUTTER_API_VERSION@/clutter
 libclutterinclude_HEADERS = clutter-osx.h
 
 INCLUDES = \
-	-DG_LOG_DOMAIN=\"ClutterOSX\" \
-        -DCLUTTER_COMPILATION \
-	-I$(top_srcdir) \
-	-I$(top_srcdir)/clutter \
-	-I$(top_builddir)/clutter \
-	$(CLUTTER_CFLAGS) \
-	$(CLUTTER_DEBUG_CFLAGS) \
-	$(MAINTAINER_CFLAGS)
-	-xobjective-c
+	-DG_LOG_DOMAIN=\"ClutterOSX\" 	\
+	-DCLUTTER_COMPILATION 		\
+	-I$(top_srcdir) 		\
+	-I$(top_srcdir)/clutter 	\
+	-I$(top_builddir)/clutter
 
-LDADD = $(CLUTTER_LIBS)
+common_ldadd = $(CLUTTER_LIBS)
 
 noinst_LTLIBRARIES = libclutter-osx.la
 
-libclutter_osx_la_SOURCES = \
-	clutter-backend-osx.h \
-	clutter-backend-osx.c \
-	clutter-event-osx.c \
-	clutter-stage-osx.h \
-	clutter-stage-osx.c \
+libclutter_osx_la_CFLAGS = $(CLUTTER_CFLAGS) $(CLUTTER_DEBUG_CFLAGS) $(MAINTAINER_CFLAGS) -xobjective-c
+libclutter_osx_la_LDADD = $(common_ldadd)
+libclutter_osx_la_SOURCES = 	\
+	clutter-backend-osx.h 	\
+	clutter-backend-osx.c 	\
+	clutter-event-osx.c 	\
+	clutter-stage-osx.h 	\
+	clutter-stage-osx.c 	\
 	clutter-osx.h