less(1): fix some memory leaks

This does not fix all "leaks" that may be detected. In particular during program initialization copies of a few strings and such are made and those copies may persist. However, those are benign as the program does not continuously leak memory. Furthermore, fixing all of them would be substantial

less(1): carefully handle null in strchr arguments

The environment variable LESSBINFMT is not properly validated. If it is set to "*", less will perform an out of boundary access. This happens because strchr can be called with '\0' as second argument. Such a call won't return NULL but the address of the '\0' in the string. Therefore, the checkfmt

sort(1): fix segfault with -m flag

sort segfaults when using the -m flag and no files. It should default to stdin instead. Easily reproducible with a simple: sort -m Index: sort.c === RCS file: /cvs/src/usr.bin/sort/sort.c,v retrieving revision 1.86 diff -u -r1.86 sor

xargs(1): remove unused variable

The repllen variable is not used anywhere. Index: strnsubst.c === RCS file: /cvs/src/usr.bin/xargs/strnsubst.c,v retrieving revision 1.5 diff -u -r1.5 strnsubst.c --- strnsubst.c 27 Oct 2009 23:59:50 - 1.5 +++ strnsubst.c 3 J