[PATCH] tests: allow tests to append tunables

[Yury Khrustalev]

On Tue, Mar 24, 2026 at 02:14:38PM +0000, Yury Khrustalev wrote:
> Many tests use Glibc tunables. The tunable values are provided via
> the GLIBC_TUNABLES env variable. Tests set it in makefiles using
> 
>   tst-foo-ENV = GLIBC_TUNABLES=tunable=value
> 
> This overwrites environment for this test, so if another env var is
> set elsewhere, one of these changes would be lost. The correct way
> should be to append to test's environment:
> 
>   tst-foo-ENV += GLIBC_TUNABLES=tunable=value
> 
> However, if two or more tunables need to be set for the same test,
> the 'tunable=value' part should be appended to previously defined
> GLIBC_TUNABLES env variable.
> 
> This commit adds 'tunable-add' that can be used to correctly append
> another tunable to a test's environment. We also change tests in the
> malloc and misc folder.
> 
> ---
> base-commit: 9f5f18aab4
> passes regression on aarch64 and x86-64

Polite ping :)