Xalloc dedup&cleanup

[BenBE]

This cleans up some of the mess in XAlloc.h …

This also fixes an argument list issue the original macro had (buf was missing and wrongly labelled fmt).

[fasterit]

Thank you very much for cleaning up. Much appreciated!

Can we have these in StringUtils please?
Nobody would expect them in XAlloc.

[BenBE]

Given the naming I somewhat expected them to be there. Inside XAlloc.* all the functions start with a lowercase x. For those functions to properly fit the naming for StringUtils.c/.h They should be named String_asnprintf, String_snprintf and String_strdup instead (to stay consistent).

I could rename and move them over to StringUtils.c/.h, but doing so is better suited in a separate PR IMHO.

[BenBE]

Thank you very much for cleaning up. Much appreciated!

Can we have these in StringUtils please?
Nobody would expect them in XAlloc.

I did a dryrun with just moving these functions (without rename) and that patch already causes quite a disruption. And with proper renaming (which IMHO should be done when moving these functions over to StringUtils.h) causes not just about 20 files, but nearly 100 that would need changes; across all platforms. Furthermore I'd have to redo quite a bit of #156 and #160; thus moving those functions is best done after #160 (which also allows to better clean up after this change).

Thus I'd prefer to go along with #155 as-is for now.