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)
Edited by Jens Petersen