Modification of environment variables on Windows

[Markus Mützel]

Dear gnulib developers,

We recently updated gnulib in GNU Octave to a newer revision 
(d4ec02b3cc70cddaaa5183cc5a45814e0afb2292). (Kudos on the impressive speedup to 
the bootstrap process.)

Since then, we are seeing warnings like the following when building for MinGW:

../../libgnu/tzset.c: In function 'rpl_tzset':
../../libgnu/tzset.c:68:24: warning: initialization of 'char *' from 
incompatible pointer type 'char **' [-Wincompatible-pointer-types]
   68 |         for (char *s = env; *s != NULL; s++)
      |                        ^~~
../../libgnu/tzset.c:68:32: warning: comparison between pointer and integer
   68 |         for (char *s = env; *s != NULL; s++)
      |                                ^~
../../libgnu/tzset.c:72:28: warning: initialization of 'wchar_t *' {aka 'short 
unsigned int *'} from incompatible pointer type 'wchar_t **' {aka 'short 
unsigned int **'} [-Wincompatible-pointer-types]
   72 |         for (wchar_t *ws = wenv; *ws != NULL; ws++)
      |                            ^~~~
../../libgnu/tzset.c:72:38: warning: comparison between pointer and integer
   72 |         for (wchar_t *ws = wenv; *ws != NULL; ws++)
                                             ^~

IIUC, these warnings might be legitimate.

The attached patch avoids those warnings.

I'm hoping this is the correct format to propose changes to gnulib.

Best,
Markus Mützel

0001-ctime-localtime-tzset-wcsftime-Check-content-of-envi.patch
Description: Text document