Add symbol versioning for shared libraries

Based on patch by Reinhard Tartler <siretart tauware de>

Originally committed as revision 21236 to svn://svn.ffmpeg.org/ffmpeg/trunk

common.mak

@@ -9,6 +9,7 @@ vpath %.c   $(SRC_DIR)
 vpath %.h   $(SRC_DIR)
 vpath %.S   $(SRC_DIR)
 vpath %.asm $(SRC_DIR)
+vpath %.v   $(SRC_DIR)
 
 ifeq ($(SRC_DIR),$(SRC_PATH_BARE))
 BUILD_ROOT_REL = .
@@ -33,6 +34,9 @@ CPPFLAGS := -DHAVE_AV_CONFIG_H -I$(BUILD_ROOT_REL) -I$(SRC_PATH) $(CPPFLAGS)
 
 %$(EXESUF): %.c
 
+%.ver: %.v
+	sed 's/$$MAJOR/$($(basename $(@F))_VERSION_MAJOR)/' $^ > $@
+
 SVN_ENTRIES = $(SRC_PATH_BARE)/.svn/entries
 ifeq ($(wildcard $(SVN_ENTRIES)),$(SVN_ENTRIES))
 $(BUILD_ROOT_REL)/version.h: $(SVN_ENTRIES)
@@ -77,7 +81,7 @@ $(HOSTPROGS): %$(HOSTEXESUF): %.o
 DEPS := $(OBJS:.o=.d)
 depend dep: $(DEPS)
 
-CLEANSUFFIXES     = *.d *.o *~ *.ho *.map
+CLEANSUFFIXES     = *.d *.o *~ *.ho *.map *.ver
 DISTCLEANSUFFIXES = *.pc
 LIBSUFFIXES       = *.a *.lib *.so *.so.* *.dylib *.dll *.def *.dll.a *.exp
 

configure

@@ -1561,6 +1561,7 @@ tmpfile TMPE  $EXESUF
 tmpfile TMPH  .h
 tmpfile TMPO  .o
 tmpfile TMPS  .S
+tmpfile TMPV  .ver
 tmpfile TMPSH .sh
 
 unset -f mktemp
@@ -2568,6 +2569,10 @@ check_ldflags -Wl,--as-needed
 check_ldflags '-Wl,-rpath-link,\$(BUILD_ROOT)/libpostproc -Wl,-rpath-link,\$(BUILD_ROOT)/libswscale -Wl,-rpath-link,\$(BUILD_ROOT)/libavfilter -Wl,-rpath-link,\$(BUILD_ROOT)/libavdevice -Wl,-rpath-link,\$(BUILD_ROOT)/libavformat -Wl,-rpath-link,\$(BUILD_ROOT)/libavcodec -Wl,-rpath-link,\$(BUILD_ROOT)/libavutil'
 check_ldflags -Wl,-Bsymbolic
 
+echo "X{};" > $TMPV
+test_ldflags -Wl,--version-script,$TMPV &&
+    append SHFLAGS '-Wl,--version-script,\$(SUBDIR)lib\$(NAME).ver'
+
 if enabled small; then
     check_cflags -Os            # not all compilers support -Os
     optimizations="small"

libavcodec/libavcodec.v

+LIBAVCODEC_$MAJOR {
+        global: *;
+};

libavdevice/libavdevice.v

+LIBAVDEVICE_$MAJOR {
+        global: avdevice_*;
+        local: *;
+};

libavfilter/libavfilter.v

+LIBAVFILTER_$MAJOR {
+        global: avfilter_*; av_*;
+        local: *;
+};

libavformat/libavformat.v

+LIBAVFORMAT_$MAJOR {
+        global: *;
+};

libavutil/libavutil.v

+LIBAVUTIL_$MAJOR {
+        global: av_*; ff_*; avutil_*;
+        local: *;
+};

libpostproc/libpostproc.v

+LIBPOSTPROC_$MAJOR {
+        global: postproc_*; pp_*;
+        local: *;
+};

subdir.mak

@@ -51,7 +51,7 @@ install-libs: install-lib$(NAME)-shared
 $(SUBDIR)$(SLIBNAME): $(SUBDIR)$(SLIBNAME_WITH_MAJOR)
 	cd ./$(SUBDIR) && $(LN_S) $(SLIBNAME_WITH_MAJOR) $(SLIBNAME)
 
-$(SUBDIR)$(SLIBNAME_WITH_MAJOR): $(OBJS)
+$(SUBDIR)$(SLIBNAME_WITH_MAJOR): $(OBJS) $(SUBDIR)lib$(NAME).ver
 	$(SLIB_CREATE_DEF_CMD)
 	$(LD) $(SHFLAGS) $(FFLDFLAGS) -o $$@ $$(filter %.o,$$^) $(FFEXTRALIBS) $(EXTRAOBJS)
 	$(SLIB_EXTRA_CMD)