RFR: 8341586: RISC-V: build fail with gcc9

[SendaoYan]

On Sun, 6 Oct 2024 14:37:44 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Not a review, just a drive-by comment.
> 
> It's unclear from the report whether the issue is with gcc9, or with gcc9+. Note that gcc10 is the minimum supported version since JDK 23. So maybe this isn't really an issue for JDK 23+.
> 
> (I'm surprised configuring JDK 24 with gcc9 works, rather than failing with a complaint about not meeting the minimum required compiler version.)
> 
> https://github.com/openjdk/jdk/blame/50426b3841240c5fda0df11439e52fa1ae9e7e07/make/autoconf/toolchain.m4#L53

If build jdk24 with gcc version below gcc10, the configure script will print a warning like `WARNING: You are using gcc 2.32 which is older than 10.0. This is not a supported configuration.`.

And the detected gcc version is not correct, the actual gcc version is `gcc version 10.2.1 20200825 (Alibaba 10.2.1-3.8 2.32) (GCC) `

This issue influence jdk11/17/21, so I think it's better to fix this issue in mainline first.

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PR Comment: https://git.openjdk.org/jdk/pull/21376#issuecomment-2395480854