I doubt -DWINNT is needed

Change-Id: Ic88b4705c4fa79ac5be325c1a4d3cc881d514b6c

avmedia/Library_avmediagst.mk

@@ -22,12 +22,6 @@ $(eval $(call gb_Library_use_external,avmediagst,boost_headers))
 
 $(eval $(call gb_Library_use_sdk_api,avmediagst))
 
-ifeq ($(OS),WNT)
-$(eval $(call gb_Library_add_defs,avmediagst,\
-	-DWINNT
-))
-endif
-
 $(eval $(call gb_Library_use_libraries,avmediagst,\
 	comphelper \
 	cppu \

avmedia/Library_avmediagst_0_10.mk

@@ -24,12 +24,6 @@ $(eval $(call gb_Library_use_externals,avmediagst_0_10,\
 
 $(eval $(call gb_Library_use_sdk_api,avmediagst_0_10))
 
-ifeq ($(OS),WNT)
-$(eval $(call gb_Library_add_defs,avmediagst_0_10,\
-	-DWINNT
-))
-endif
-
 $(eval $(call gb_Library_use_libraries,avmediagst_0_10,\
 	comphelper \
 	cppu \

avmedia/Library_avmediavlc.mk

@@ -20,12 +20,6 @@ $(eval $(call gb_Library_use_external,avmediavlc,boost_headers))
 
 $(eval $(call gb_Library_use_sdk_api,avmediavlc))
 
-ifeq ($(OS),WNT)
-$(eval $(call gb_Library_add_defs,avmediavlc,\
-    -DWINNT \
-))
-endif
-
 $(eval $(call gb_Library_use_externals,avmediavlc,\
 	boost_headers \
 	boostsystem \