Integrated: 8368468: Split out everything but configure results from spec.gmk

[Magnus Ihse Bursie]

On Tue, 23 Sep 2025 13:48:20 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> Most of spec.gmk contains lines on the form:
> 
> VAR := @VAR@
> 
> which are setup using `AC_SUBST(VAR)` in the configure script. However, there are also some other stuff there, which are mostly put there since we had no other good place to do so.
> 
> I have now created a new file, `CommonVars.gmk`, which is automatically included, and moved everything but pure configure assignments from `spec.gmk` into this file.
> 
> That makes `spec.gmk` a great interface between configure and make -- the job of configure is to fill in `spec.gmk`, plain and simple.
> 
> This refactoring also points to additional future improvements, e.g. generating `spec.gmk` automatically from all `AC_SUBST` statements, and to clean up the new `CommonVars.gmk`. Right now I kept all lines in the same order as they appeared in `spec.gmk.template`, to minimize risk of unintentional changes (we have some non-`:=` assignments), and to facilitate comparison for this patch. It is also clear that we have room for improvement in how we do bootcycle-builds and build the build-jdk. My current solution is to keep the special spec files, even if they just set a single special flag, to minimize impact of this patch.

This pull request has now been integrated.

Changeset: de1f5a3c
Author:    Magnus Ihse Bursie <ihse at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/de1f5a3c437ab4c6009f8be6f9f109ed36fb0b53
Stats:     938 lines in 12 files changed: 472 ins; 413 del; 53 mod

8368468: Split out everything but configure results from spec.gmk

Reviewed-by: erikj

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PR: https://git.openjdk.org/jdk/pull/27452