Add custom vendor for Openjdk

[Hax4us]

i noticed one thing that there is no any specific system property in current build of openjdk-17 by which i can differentiate Android (arm) and Linux (arm) so i was thinking that we should set some property like --with-vendor-name Android or Termux, what you think about it ?

and yes i know there are many things i can do from code but i think it would be elegant solution.
And i saw many projects on github which supports Android but failed to detect Android platform on Termux. bcz all of them were using system properties for platform detection like java.vendor , java.runtime.name , java.vm.vendor etc
So its clear those projects were made for Android but with dalvikvm. and dalvikvm has all properties set appropriately.

[thunder-coding]

I feel this is eligible for a bug report. Not a Java developer but there must be someone who can give proper guidance/views on what should be done for this.