RFR: 8224087: Compile C code for at least C99 Standard compliance

[Andrew Haley]

On 5/20/19 8:40 AM, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8224087
> webrev: http://cr.openjdk.java.net/~dholmes/8224087/webrev/
> 
> The need to remove a for-loop declaration expression to appease gcc 4.8 
> annoyed me enough to investigate setting C99 as our minimum allow 
> C-language level when compiling. It turned out to be a lot more complex 
> a situation than I thought due to toolchain quirks. See lots of details 
> in the bug report.
> 
> To summarise the changes:
> - gcc: force to -std=gnu99
> - clang force to -std=gnu99
> - Solaris studio - no effective change
> - Visual Studio - no change
> - xlc - no effective change (but we use the explicit flag rather than 
> accepting it as default)
> 
> I've checked how this works with all the toolchains except xlc as I have 
> no access to that. Some assistance from someone who can verify the 
> correctness on xlc would be appreciated.

You are a hero for doing this. Thank you, thank you!

Approved by me, checking only Linux targets.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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