Define RUBY_FULL_REVISION

Only if the short revision differs from the full revision.

tool/file2lastrev.rb

@@ -54,9 +54,10 @@ vcs = nil
     }
   when :revision_h
     Proc.new {|last, changed, modified, branch, title|
+      short = vcs.short_revision(last)
       [
-        "#define RUBY_REVISION #{vcs.short_revision(last).dump}",
-        "#define RUBY_FULL_REVISION #{last.dump}",
+        "#define RUBY_REVISION #{short.inspect}",
+        ("#define RUBY_FULL_REVISION #{last.inspect}" unless short == last),
         if branch
           e = '..'
           limit = 16

tool/make-snapshot

@@ -291,7 +291,13 @@ def package(vcs, rev, destdir, tmp = nil)
     v = v[0]
   end
 
-  open("#{v}/revision.h", "wb") {|f| f.puts "#define RUBY_REVISION #{revision.dump}"}
+  open("#{v}/revision.h", "wb") {|f|
+    short = vcs.short_revision(revision)
+    f.puts "#define RUBY_REVISION #{short.inspect}"
+    unless short == revision
+      f.puts "#define RUBY_FULL_REVISION #{revision.inspect}"
+    end
+  }
   version ||= (versionhdr = IO.read("#{v}/version.h"))[RUBY_VERSION_PATTERN, 1]
   version ||=
     begin