hg: jdk/submit: 8238542: When warning about C/C++ compiler mismatch, be clear if this is about build compilers

[magnus.ihse.bursie at oracle.com]

Changeset: 227542943648
Author:    ihse
Date:      2020-02-06 13:40 +0100
URL:       https://hg.openjdk.java.net/jdk/submit/rev/227542943648

8238542: When warning about C/C++ compiler mismatch, be clear if this is about build compilers
Reviewed-by: erikj

! make/autoconf/toolchain.m4