Fix how link dependencies are specified

Several target have their dependencies incorrectly reported in _LDFLAGS
variables instead of _LIBADD or _LDADD. As a result, the link flag
-Wl,--as-needed (when used) is misplaced making it useless. This patch
sanetizes this a little bit.

src/Makefile-hotplug-sniffer.am

@@ -15,7 +15,7 @@ cinnamon_hotplug_sniffer_CFLAGS =		\
 	$(CINNAMON_HOTPLUG_SNIFFER_CFLAGS)		\
 	$(NULL)
 
-cinnamon_hotplug_sniffer_LDFLAGS =		\
+cinnamon_hotplug_sniffer_LDADD =		\
 	$(CINNAMON_HOTPLUG_SNIFFER_LIBS)		\
 	$(NULL)
 

src/Makefile-st.am

@@ -175,7 +175,6 @@ libst_1_0_la_SOURCES =				\
 	$(st_built_sources)			\
 	$(NULL)
 libst_1_0_la_CPPFLAGS = $(st_cflags)
-libst_1_0_la_LDFLAGS = $(LDADD)
 
 noinst_PROGRAMS += test-theme
 

src/Makefile-tray.am

@@ -49,7 +49,6 @@ libtray_la_SOURCES =		\
 	$(tray_built_sources)	\
 	$(NULL)
 libtray_la_CPPFLAGS = $(tray_cflags)
-libtray_la_LDFLAGS = $(LDADD)
 
 CLEANFILES += $(TRAY_STAMP_FILES) $(BUILT_SOURCES)