misc: eliminate all those remaining gcc -Wall warnings

Reference(s):
proc/readproc.c: In function 'statm2proc'
proc/readproc.c:600:9: warning: variable 'num' set but not used [-Wunused-but-set-variable]

proc/stat.c: In function 'stat_derive_unique':
proc/stat.c:429:1: warning: no return statement in function returning non-void [-Wreturn-type]

ps/parser.c: In function 'arg_type':
ps/parser.c:1098:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
ps/parser.c:1099:34: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'

lib/signals.c: In function 'strtosig':
lib/signals.c:243:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
lib/signals.c:245:13: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'

slabtop.c: In function 'print_summary':
slabtop.c:223:29: warning: unused variable 'stats' [-Wunused-variable]

watch.c: In function 'process_ansi':
watch.c:232:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
watch.c:235:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'

Signed-off-by: Jim Warner <james.warner@comcast.net>

proc/stat.c

@@ -415,7 +415,7 @@ static inline void stat_cleanup_stacks_all (
 } // end: stat_cleanup_stacks_all
 
 
-static inline int stat_derive_unique (
+static inline void stat_derive_unique (
         struct hist_tic *this)
 {
     /* note: we exclude guest tics from xtot since ...