From accb06120c13a4ead442464d96f2fa318fa07a4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Thu, 24 Aug 2017 23:27:16 +0300
Subject: [PATCH] configure: Use dllexport/dllimport for data symbols across
 DLLs with mingw
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This avoids having to use pseudo relocations.

The version script used for exporting functions is skipped as soon
as the set of object files contains symbols marked with dllexport,
therefore we need to use makedef to produce the full list of symbols
to be exported.

Signed-off-by: Martin Storsjö <martin@martin.st>
---
 configure             | 11 +++++++++--
 libavcodec/internal.h |  2 +-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index b995235708..c24cdd4f7e 100755
--- a/configure
+++ b/configure
@@ -4026,6 +4026,10 @@ case $target_os in
         if enabled x86_64; then
             LIBTARGET="i386:x86-64"
         fi
+        if enabled shared; then
+            # Cannot build both shared and static libs when using dllexport.
+            disable static
+        fi
         check_ldflags -Wl,--nxcompat
         check_ldflags -Wl,--dynamicbase
         shlibdir_default="$bindir_default"
@@ -4033,12 +4037,13 @@ case $target_os in
         SLIBSUF=".dll"
         SLIBNAME_WITH_VERSION='$(SLIBPREF)$(NAME)-$(LIBVERSION)$(SLIBSUF)'
         SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(NAME)-$(LIBMAJOR)$(SLIBSUF)'
-        SLIB_EXTRA_CMD=-'sed -e "s/ @[^ ]*//" $$(@:$(SLIBSUF)=.orig.def) > $$(@:$(SLIBSUF)=.def); $(DLLTOOL) -m $(LIBTARGET) -d $$(@:$(SLIBSUF)=.def) -l $(SUBDIR)$(SLIBNAME:$(SLIBSUF)=.lib) -D $(SLIBNAME_WITH_MAJOR)'
+        SLIB_EXTRA_CMD=-'$(DLLTOOL) -m $(LIBTARGET) -d $$(@:$(SLIBSUF)=.def) -l $(SUBDIR)$(SLIBNAME:$(SLIBSUF)=.lib) -D $(SLIBNAME_WITH_MAJOR)'
         SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
         SLIB_INSTALL_LINKS=
         SLIB_INSTALL_EXTRA_SHLIB='$(SLIBNAME:$(SLIBSUF)=.lib)'
         SLIB_INSTALL_EXTRA_LIB='lib$(SLIBNAME:$(SLIBSUF)=.dll.a) $(SLIBNAME_WITH_MAJOR:$(SLIBSUF)=.def)'
-        SHFLAGS='-shared -Wl,--output-def,$$(@:$(SLIBSUF)=.orig.def) -Wl,--out-implib,$(SUBDIR)lib$(SLIBNAME:$(SLIBSUF)=.dll.a) -Wl,--enable-runtime-pseudo-reloc -Wl,--enable-auto-image-base'
+        SLIB_CREATE_DEF_CMD='ARCH="$(ARCH)" AR="$(AR_CMD)" NM="$(NM_CMD)" $(SRC_PATH)/compat/windows/makedef $(SUBDIR)lib$(NAME).ver $(OBJS) > $$(@:$(SLIBSUF)=.def)'
+        SHFLAGS='-shared -Wl,--out-implib,$(SUBDIR)lib$(SLIBNAME:$(SLIBSUF)=.dll.a) -Wl,--enable-auto-image-base $$(@:$(SLIBSUF)=.def)'
         enabled x86_64 && objformat="win64" || objformat="win32"
         dlltool="${cross_prefix}dlltool"
         ranlib=:
@@ -5432,6 +5437,8 @@ DEPX86ASMFLAGS=\$(X86ASMFLAGS)
 AR=$ar
 ARFLAGS=$arflags
 AR_O=$ar_o
+AR_CMD=$ar
+NM_CMD=$nm
 RANLIB=$ranlib
 STRIP=$strip
 LN_S=$ln_s
diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index 0efe34f667..da1b2fa7d1 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -285,7 +285,7 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame);
  */
 AVCPBProperties *ff_add_cpb_side_data(AVCodecContext *avctx);
 
-#if defined(_MSC_VER) && CONFIG_SHARED
+#if defined(_WIN32) && CONFIG_SHARED
 #ifdef BUILDING_avcodec
 #    define av_export_avcodec __declspec(dllexport)
 #else