Building jruby in git-free environment fails

The ant tasks to build jruby require git to succeed.
build.xml, lines 195-200, 1736-1738

I would recommend following one of the three options:

1. Add documentation to the build instructions regarding this requirement (not best choice, another pending bug to be file regarding git usage)
2. Remove git requirements in build (currently my solution, by deleting lines 195-200 and 1734-1738)
   This may have some unknown (to me) effect based on joda-time jar not being updated
3. Have a more graceful failure case. Currently, the failure case is non-intuitive, eg:

   update-constants:
        [echo] Updating constants with tzdata version 2010k
        [exec] Result: 1
        [copy] Warning: Could not find file C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java to copy.
        [copy] Copying 1 file to C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime
   
   _uc_internal_:
        [copy] Copying 1 file to C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime
       [javac] Compiling 1 source file to C:\[REMOVED]\jruby-1.6.2\build\classes\jruby
       [javac] C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java:62: unclosed string literal
       [javac]         REVISION = "'git' is not recognized as an internal or external command,
       [javac]                    ^
       [javac] C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java:63: ';' expected
       [javac] operable program or batch file.";
       [javac]                 ^
       [javac] C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java:63: ';' expected
       [javac] operable program or batch file.";
       [javac]                          ^
       [javac] C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java:63: unclosed string literal
       [javac] operable program or batch file.";
       [javac]                                ^
       [javac] C:\[REMOVED]\jruby-1.6.2\src_gen\org\jruby\runtime\Constants.java:63: not a statement
       [javac] operable program or batch file.";
       [javac]                               ^
       [javac] 5 errors
   

from src_gen\org\jruby\runtime\Constants.java:

    static {
        // This is populated here to avoid javac propagating the value to consumers
        REVISION = "'git' is not recognized as an internal or external command,
operable program or batch file.";
    }