swprintf ignores the grouping flag

[bhaible]

swprintf, as specified by POSIX ​https://pubs.opengroup.org/onlinepubs/9799919799/functions/swprintf.html , should support the apostrophe character as a grouping flags in %i, %d, %u, %f, %F, %g, %G directives.

In Haiku hrev 58799, this flag is ignored.

How to reproduce: Compile and run the attached program foo.c.

$ gcc -Wall foo.c
$ ./a.out

Expected output:

thousands_sep = | | = | |
grouping = 3
1 000
1 111 111 234 567 890
1 000
1 111 111 234 567 890

Actual output:

thousands_sep = | | = | |
grouping = 3
1 000
1 111 111 234 567 890
01000
1111111234567890

[bhaible]

test case foo.c