- Add soversion.patch to workaround upstream ABI breakage.

OBS-URL: https://build.opensuse.org/package/show/multimedia:libs/ffmpeg-4?expand=0&rev=125

soversion.patch

@@ -0,0 +1,41 @@
+From: Jan Engelhardt <jengelh@inai.de>
+Date: 2020-07-04 23:56:54.411950316 +0200
+
+User frispete wrote on 2020-6-26 22:13+0000 at
+https://build.opensuse.org/package/show/multimedia:libs/ffmpeg-4#comment-1257440
+: """Unfortunately, this version is binary incompatible to 4.2.3 in some
+aspects. Chromium crashes when accessing some sites, e.g.
+https://www.xometry.com/ and push the quote button. Blender cannot export PNG
+files anymore"""
+
+And indeed:
+
+$ abidiff b42/usr/lib/debug/usr/lib64/libavcodec.so.58.54.100-4.2.3-1.1.x86_64.debug \
+          b43/usr/lib/debug/usr/lib64/libavcodec.so.58.91.100-4.3-136.2.x86_64.debug
+
+  [...] in pointed to type 'struct AVCodecContext' at avcodec.h:526:1:
+                     type size changed from 8448 to 8576 (in bits)
+  [...]
+        underlying type 'struct AVDCT' at avdct.h:29:1 changed:
+          type size changed from 896 to 960 (in bits)
+
+As this struct is made public by way of presenting it in /usr/include,
+I conclude: bad upstream, bad upstream!
+
+---
+ configure |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+Index: ffmpeg-4.3/configure
+===================================================================
+--- ffmpeg-4.3.orig/configure
++++ ffmpeg-4.3/configure
+@@ -3794,7 +3794,7 @@ SLIBPREF="lib"
+ SLIBSUF=".so"
+ SLIBNAME='$(SLIBPREF)$(FULLNAME)$(SLIBSUF)'
+ SLIBNAME_WITH_VERSION='$(SLIBNAME).$(LIBVERSION)'
+-SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
++SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)suse0'
+ LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
+ SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
+ SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'