RFR: JDK-8210283: Support git as an SCM alternative in the build

[Erik Joelsson]

New webrev: http://cr.openjdk.java.net/~erikj/8210283/webrev.02/

Fixed the comment in SourceRevision.gmk.

Added an SCM identifier in the string so a typical .src-rev file now 
looks like this:

.:hg:3f189f451ff1+

or like this:

.:git:2e1f2c6d44e5+

/Erik


On 2018-09-04 15:00, Erik Joelsson wrote:
> There are several instances of OpenJDK source being hosted in Git 
> repositories instead of Mercurial. AdoptOpenJDK is one and some 
> engineers use local conversions for their day to day work. Project 
> Skara aims to investigate Git as well. To better support this, the 
> build needs to be able to support Git as an alternative to Mercurial 
> when creating the identification hash in the release file. It would 
> also be convenient with a .gitignore file mirroring the .hgignore file.
>
> This patch adds such support as well as a .gitignore file.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8210283
>
> Webrev: http://cr.openjdk.java.net/~erikj/8210283/webrev.01/index.html
>
> /Erik
>