avformat/output-example: Declare link dependency on libswscale in the Makefile

common.mak

@@ -25,7 +25,8 @@ TOOLOBJS  := $(TOOLS:%=tools/%.o)
 TOOLS     := $(TOOLS:%=tools/%$(EXESUF))
 HEADERS   += $(HEADERS-yes)
 
-DEP_LIBS := $(foreach NAME,$(FFLIBS),lib$(NAME)/$($(CONFIG_SHARED:yes=S)LIBNAME))
+PATH_LIBNAME = $(foreach NAME,$(1),lib$(NAME)/$($(CONFIG_SHARED:yes=S)LIBNAME))
+DEP_LIBS := $(foreach lib,$(FFLIBS),$(call PATH_LIBNAME,$(lib)))
 
 SRC_DIR    := $(SRC_PATH)/lib$(NAME)
 ALLHEADERS := $(subst $(SRC_DIR)/,$(SUBDIR),$(wildcard $(SRC_DIR)/*.h $(SRC_DIR)/$(ARCH)/*.h))

libavformat/Makefile

@@ -400,3 +400,4 @@ TOOLS     = aviocat                                                     \
             probetest                                                   \
 
 $(SUBDIR)output-example$(EXESUF): ELIBS = $(patsubst %,$(LD_LIB),swscale avutil)
+$(SUBDIR)output-example$(EXESUF): $(call PATH_LIBNAME,swscale)