RFR: JDK-8323008: filter out any -std* flags added by autoconf from CC/CXX [v2]

[Matthias Baesken]

> It was observed, that autoconf 2.72 added on macOS x86_64 the flag -std=gnu++11 by default to CXX in the configure process .
> This is not really wanted so better remove / filter out any -std* flags added by autoconf from CC/CXX .
> 
> Seems we have something similar for some time for CFLAGS and CXXFLAGS ( see TOOLCHAIN_POST_DETECTION in make/autoconf/toolchain.m4) that
>  dates back to JDK 9.
> 
> See the discussion about this issue : https://mail.openjdk.org/pipermail/build-dev/2024-January/042551.html

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Adjust GREP call

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17301/files
  - new: https://git.openjdk.org/jdk/pull/17301/files/ce2ef781..63300451

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17301&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17301&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17301.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17301/head:pull/17301

PR: https://git.openjdk.org/jdk/pull/17301