ardour: simplify version handling

pkgs/applications/audio/ardour/default.nix

@@ -17,10 +17,6 @@ let
   # Version to build.
   tag = "4.1";
 
-  # Version info that is built into the binary. Keep in sync with 'tag'. The
-  # last 8 digits is a (fake) commit id.
-  revision = "4.1-fe672c8";
-
 in
 
 stdenv.mkDerivation rec {
@@ -42,7 +38,7 @@ stdenv.mkDerivation rec {
     ];
 
   patchPhase = ''
-    printf '#include "libs/ardour/ardour/revision.h"\nnamespace ARDOUR { const char* revision = \"${revision}\"; }\n' > libs/ardour/revision.cc
+    printf '#include "libs/ardour/ardour/revision.h"\nnamespace ARDOUR { const char* revision = \"${tag}-${builtins.substring 0 8 src.rev}\"; }\n' > libs/ardour/revision.cc
     sed 's|/usr/include/libintl.h|${glibc}/include/libintl.h|' -i wscript
     patchShebangs ./tools/
   '';