Compilation error in timing lib with recent compiler

[bartgol]

I ran into this error

/home/runner/work/E3SM/E3SM/e3sm/source/components/homme/utils/cime/CIME/non_py/src/timing/private.h:47:15: error: cannot use keyword 'false' as enumeration constant
   47 | typedef enum {false = 0, true = 1} bool;  /* mimic C++ */
      |               ^~~~~
/home/runner/work/E3SM/E3SM/e3sm/source/components/homme/utils/cime/CIME/non_py/src/timing/private.h:47:15: note: 'false' is a keyword with '-std=c23' onwards

I was using gcc 15.2.0 in a containerized build. I think these lines

#ifndef __cplusplus
typedef enum {false = 0, true = 1} bool;  /* mimic C++ */
#endif

should be upgraded to

#if !defined(__cplusplus) && __STDC_VERSION__ < 202311L
typedef enum {false = 0, true = 1} bool;  /* mimic C++ */
#endif

Does this seem reasonable?

[jedwards4b]

It doesn't seem unreasonable. I take it newer versions of STDC don't need this?

[bartgol]

Correct. I edited the opening msg to include the full compiler explanation.

This seems to be the C23 change.

I'll submit a quick PR, no rush to integrate, as I downgraded to gcc 13.2 for my CI testing, so I am ok for now.

[jedwards4b]

Sounds good, thank you!

[rljacob]

attn: @amametjanov