RFR: 8323672: Suppress unwanted autoconf added flags in CC and CXX [v2]

[Julian Waters]

> [JDK-8323008](https://bugs.openjdk.org/browse/JDK-8323008) reports unwanted autoconf flags being added to the command line, and solves the issue by filtering out the added flags by force. This is not optimal however, as doing so leaves the autoconf message that the flags were added still displaying during the configure process, which is confusing. Instead, setting a couple of fields to disable the autoconf internals responsible for the unwanted flag is a cleaner solution

Julian Waters has updated the pull request incrementally with one additional commit since the last revision:

  make/autoconf/toolchain.m4
  
  Co-authored-by: Magnus Ihse Bursie <mag at icus.se>

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/17401/files
  - new: https://git.openjdk.org/jdk/pull/17401/files/b39e0479..0de14523

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17401&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17401&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17401.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17401/head:pull/17401

PR: https://git.openjdk.org/jdk/pull/17401