Fix strcmp namespace in HIP

[NamjaeChoi]

strcmp requires std namespace when used from cstdlib header. It fails to compile with the latest hipcc.

[jeremylt]

which version of ROCm, for posterity?

[NamjaeChoi]

We are currently testing 7.2.4.

[jeremylt]

I think @zatkins-dev 7.2 working well but 7.3 currently is buggy with the same code?

[NamjaeChoi]

Additional information that may be helpful for clarity is that we are building libCEED through PETSc.

[zatkins-dev]

I think @zatkins-dev 7.2 working well but 7.3 currently is buggy with the same code?

At least on GFX906, 7.2+ cause a ton of test failures. 7.1.x is the last known good version.

[zatkins-dev]

This fix is totally reasonable though, we should fix namespacing issues

[NamjaeChoi]

Actually the code compiles as is. Sorry for a confusion, even though the change isn't harmful. I realized that the libCEED version PETSc is pointing is missing #include <cstring>.

[jeremylt]

Ah the correct fix is probably to update the libCEED hash PETSc is using