build: allow targets to specify extra objects to link with executables

This allows targets to include special objects when linking
executables without including them in (shared) libraries.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Makefile

@@ -59,7 +59,7 @@ PROGS-$(CONFIG_AVPROBE)  += avprobe
 PROGS-$(CONFIG_AVSERVER) += avserver
 
 PROGS      := $(PROGS-yes:%=%$(EXESUF))
-OBJS        = cmdutils.o
+OBJS        = cmdutils.o $(EXEOBJS)
 OBJS-avconv = avconv_opt.o avconv_filter.o
 TESTTOOLS   = audiogen videogen rotozoom tiny_psnr base64
 HOSTPROGS  := $(TESTTOOLS:%=tests/%) doc/print_options
@@ -90,8 +90,8 @@ FF_DEP_LIBS  := $(DEP_LIBS)
 
 all: $(PROGS)
 
-$(TOOLS): %$(EXESUF): %.o
-	$(LD) $(LDFLAGS) $(LD_O) $< $(ELIBS)
+$(TOOLS): %$(EXESUF): %.o $(EXEOBJS)
+	$(LD) $(LDFLAGS) $(LD_O) $^ $(ELIBS)
 
 tools/cws2fws$(EXESUF): ELIBS = $(ZLIB)
 
@@ -124,7 +124,7 @@ endef
 $(foreach D,$(FFLIBS),$(eval $(call DOSUBDIR,lib$(D))))
 
 define DOPROG
-OBJS-$(1) += $(1).o cmdutils.o
+OBJS-$(1) += $(1).o cmdutils.o $(EXEOBJS)
 $(1)$(EXESUF): $$(OBJS-$(1))
 $$(OBJS-$(1)): CFLAGS  += $(CFLAGS-$(1))
 $(1)$(EXESUF): LDFLAGS += $(LDFLAGS-$(1))

configure

@@ -3737,6 +3737,7 @@ ZLIB=$($ldflags_filter -lz)
 LIB_INSTALL_EXTRA_CMD=$LIB_INSTALL_EXTRA_CMD
 EXTRALIBS=$extralibs
 COMPAT_OBJS=$compat_objs
+EXEOBJS=$exeobjs
 INSTALL=install
 LIBTARGET=${LIBTARGET}
 SLIBNAME=${SLIBNAME}

library.mak

@@ -36,7 +36,7 @@ define RULES
 $(EXAMPLES) $(TOOLS): THISLIB = $(FULLNAME:%=$(LD_LIB))
 $(TESTPROGS):         THISLIB = $(SUBDIR)$(LIBNAME)
 
-$(EXAMPLES) $(TESTPROGS) $(TOOLS): %$(EXESUF): %.o
+$(EXAMPLES) $(TESTPROGS) $(TOOLS): %$(EXESUF): %.o $(EXEOBJS)
 	$$(LD) $(LDFLAGS) $$(LD_O) $$(filter %.o,$$^) $$(THISLIB) $(FFEXTRALIBS) $$(ELIBS)
 
 $(SUBDIR)$(SLIBNAME): $(SUBDIR)$(SLIBNAME_WITH_MAJOR)