shared object on mac osx

Change-Id: Ibf357eb492e7d5883fbdf1ddf455e28767c1d65d

build/make/Makefile

@@ -249,10 +249,25 @@ $(1):
 	$(if $(quiet),@echo "    [LD] $$@")
 	$(qexec)$$(LD) -shared $$(LDFLAGS) \
             -Wl,--no-undefined -Wl,-soname,$$(SONAME) \
-            -Wl,--version-script,$$(SO_VERSION_SCRIPT) -o $$@ \
+            -Wl,--version-script,$$(EXPORTS_FILE) -o $$@ \
             $$(filter %.o,$$^) $$(extralibs)
 endef
 
+define dl_template
+# Not using a pattern rule here because we don't want to generate empty
+# archives when they are listed as a dependency in files not responsible
+# for creating them.
+$(1):
+	$(if $(quiet),@echo "    [LD] $$@")
+	$(qexec)$$(LD) -dynamiclib $$(LDFLAGS) \
+	    -exported_symbols_list $$(EXPORTS_FILE) \
+        -Wl,-headerpad_max_install_names,-compatibility_version,1.0,-current_version,$$(VERSION_MAJOR) \
+        -o $$@ \
+        $$(filter %.o,$$^) $$(extralibs)
+endef
+
+
+
 define lipo_lib_template
 $(1): $(addsuffix /$(1),$(FAT_ARCHS))
 	$(if $(quiet),@echo "    [LIPO] $$@")
@@ -317,6 +332,7 @@ LIBS=$(call enabled,LIBS)
 	@touch $@
 $(foreach lib,$(filter %_g.a,$(LIBS)),$(eval $(call archive_template,$(lib))))
 $(foreach lib,$(filter %so.$(VERSION_MAJOR).$(VERSION_MINOR).$(VERSION_PATCH),$(LIBS)),$(eval $(call so_template,$(lib))))
+$(foreach lib,$(filter %$(VERSION_MAJOR).dylib,$(LIBS)),$(eval $(call dl_template,$(lib))))
 
 INSTALL-LIBS=$(call cond_enabled,CONFIG_INSTALL_LIBS,INSTALL-LIBS)
 ifeq ($(MAKECMDGOALS),dist)

configure

@@ -453,12 +453,6 @@ EOF
 }
 
 process_detect() {
-    if enabled shared; then
-        # Can only build shared libs on a subset of platforms. Doing this check
-        # here rather than at option parse time because the target auto-detect
-        # magic happens after the command line has been parsed.
-        enabled linux || enabled win32 || enabled win64 || die "--enable-shared only supported on ELF for now"
-    fi
     if [ -z "$CC" ]; then
         echo "Bypassing toolchain for environment detection."
         enable external_build

examples.mk

@@ -162,7 +162,8 @@ BINS-$(NOT_MSVS)           += $(addprefix $(BUILD_PFX),$(ALL_EXAMPLES:.c=))
 
 # Instantiate linker template for all examples.
 CODEC_LIB=$(if $(CONFIG_DEBUG_LIBS),vpx_g,vpx)
-CODEC_LIB_SUF=$(if $(CONFIG_SHARED),.so,.a)
+SHARED_LIB_SUF=$(if $(filter darwin%,$(TGT_OS)),.dylib,.so)
+CODEC_LIB_SUF=$(if $(CONFIG_SHARED),$(SHARED_LIB_SUF),.a)
 $(foreach bin,$(BINS-yes),\
     $(if $(BUILD_OBJS),$(eval $(bin):\
         $(LIB_PATH)/lib$(CODEC_LIB)$(CODEC_LIB_SUF)))\

libs.mk

@@ -193,17 +193,29 @@ OBJS-$(BUILD_LIBVPX) += $(LIBVPX_OBJS)
 LIBS-$(if $(BUILD_LIBVPX),$(CONFIG_STATIC)) += $(BUILD_PFX)libvpx.a $(BUILD_PFX)libvpx_g.a
 $(BUILD_PFX)libvpx_g.a: $(LIBVPX_OBJS)
 
+
 BUILD_LIBVPX_SO         := $(if $(BUILD_LIBVPX),$(CONFIG_SHARED))
+
+ifeq ($(filter darwin%,$(TGT_OS)),$(TGT_OS))
+LIBVPX_SO               := libvpx.$(VERSION_MAJOR).dylib
+EXPORT_FILE             := libvpx.syms
+LIBVPX_SO_SYMLINKS      := $(addprefix $(LIBSUBDIR)/, \
+                             libvpx.dylib  )
+else
 LIBVPX_SO               := libvpx.so.$(VERSION_MAJOR).$(VERSION_MINOR).$(VERSION_PATCH)
-LIBS-$(BUILD_LIBVPX_SO) += $(BUILD_PFX)$(LIBVPX_SO)\
-                           $(notdir $(LIBVPX_SO_SYMLINKS))
-$(BUILD_PFX)$(LIBVPX_SO): $(LIBVPX_OBJS) libvpx.ver
-$(BUILD_PFX)$(LIBVPX_SO): extralibs += -lm
-$(BUILD_PFX)$(LIBVPX_SO): SONAME = libvpx.so.$(VERSION_MAJOR)
-$(BUILD_PFX)$(LIBVPX_SO): SO_VERSION_SCRIPT = libvpx.ver
+EXPORT_FILE             := libvpx.ver
+SYM_LINK                := libvpx.so
 LIBVPX_SO_SYMLINKS      := $(addprefix $(LIBSUBDIR)/, \
                              libvpx.so libvpx.so.$(VERSION_MAJOR) \
                              libvpx.so.$(VERSION_MAJOR).$(VERSION_MINOR))
+endif
+
+LIBS-$(BUILD_LIBVPX_SO) += $(BUILD_PFX)$(LIBVPX_SO)\
+                           $(notdir $(LIBVPX_SO_SYMLINKS))
+$(BUILD_PFX)$(LIBVPX_SO): $(LIBVPX_OBJS) $(EXPORT_FILE)
+$(BUILD_PFX)$(LIBVPX_SO): extralibs += -lm
+$(BUILD_PFX)$(LIBVPX_SO): SONAME = libvpx.so.$(VERSION_MAJOR)
+$(BUILD_PFX)$(LIBVPX_SO): EXPORTS_FILE = $(EXPORT_FILE)
 
 libvpx.ver: $(call enabled,CODEC_EXPORTS)
 	@echo "    [CREATE] $@"
@@ -212,10 +224,15 @@ libvpx.ver: $(call enabled,CODEC_EXPORTS)
 	$(qexec)echo "local: *; };" >> $@
 CLEAN-OBJS += libvpx.ver
 
+libvpx.syms: $(call enabled,CODEC_EXPORTS)
+	@echo "    [CREATE] $@"
+	$(qexec)awk '{print "_"$$2}' $^ >$@
+CLEAN-OBJS += libvpx.syms
+
 define libvpx_symlink_template
 $(1): $(2)
-	@echo "    [LN]      $$@"
-	$(qexec)ln -sf $(LIBVPX_SO) $$@
+	@echo "    [LN]     $(2) $$@"
+	$(qexec)ln -sf $(2) $$@
 endef
 
 $(eval $(call libvpx_symlink_template,\
@@ -225,8 +242,10 @@ $(eval $(call libvpx_symlink_template,\
     $(addprefix $(DIST_DIR)/,$(LIBVPX_SO_SYMLINKS)),\
     $(DIST_DIR)/$(LIBSUBDIR)/$(LIBVPX_SO)))
 
-INSTALL-LIBS-$(CONFIG_SHARED) += $(LIBVPX_SO_SYMLINKS)
-INSTALL-LIBS-$(CONFIG_SHARED) += $(LIBSUBDIR)/$(LIBVPX_SO)
+
+INSTALL-LIBS-$(BUILD_LIBVPX_SO) += $(LIBVPX_SO_SYMLINKS)
+INSTALL-LIBS-$(BUILD_LIBVPX_SO) += $(LIBSUBDIR)/$(LIBVPX_SO)
+
 
 LIBS-$(BUILD_LIBVPX) += vpx.pc
 vpx.pc: config.mk libs.mk