hp2ps Utilities.c: include stdlib.h instead of extern malloc and realloc

Okay this is a third and final attempt/MR to fix building hp2ps with gcc15 which defaults to C23.

It is cleaner and simpler just to import stdlib.h than extern'ing malloc and realloc explicitly.

Downstream bug: https://bugzilla.redhat.com/show_bug.cgi?id=2338570

Previous merged MR: !13853 (closed)

Hopefully this ends the saga ;o)

changed milestone to %9.14.1

added backport needed:9.10 backport needed:9.12 backport needed:9.8 labels

mentioned in issue #25662 (closed)

changed the description

changed the description

approved this merge request

assigned to @marge-bot

Thanks LGTM

I will attempt to batch this MR (!13959 (closed))...

Batch MR !13959 (closed) failed: CI failed! I will retry later...

I will attempt to batch this MR (!13962 (closed))...

Batch MR !13962 (closed) failed: CI failed! I will retry later...

I will attempt to batch this MR (!13964 (closed))...

Batch MR !13964 (closed) failed: CI failed! I will retry later...

I will attempt to batch this MR (!13966 (closed))...

Merged in 7596675e

closed