minor issues (found by cppcheck)

[Szabolcs Nagy <nsz@port70.net>]

i fixed some minor issues in my repo which were found by cppcheck
here is a list of the non-fixed ones:


[src/misc/mntent.c:32]: (portability) scanf without field width limits can crash with huge input data

getmntent_r has a sscanf with %d,
it might make sense to limit the width


[src/regex/regcomp.c:2032]: (performance) Variable 'status' is reassigned a value before the old one has been used.
[src/regex/regcomp.c:3133]: (warning) Redundant assignment of 'errcode' to itself.
[src/regex/regcomp.c:2060]: (style) Variable 'minimal_tag' is assigned a value that is never used.
[src/regex/regcomp.c:108]: (style) struct or union member 'Anonymous1::params' is never used.
[src/regex/regcomp.c:2803]: (error) Uninitialized variable: params

some of these occure multiple times,
the last two is probably worth fixing:
u.params in tre_literal_t struct is never used
and in the tre_match_empty function the params
argument is never used, but an uninitialized
pointer is passed anyway


[src/locale/strfmon.c:33]: (style) Variable 'fill' is assigned a value that is never used.
[src/stdio/vfscanf.c:134]: (style) Variable 'alloc' is assigned a value that is never used.
[src/stdio/vfwscanf.c:144]: (style) Variable 'alloc' is assigned a value that is never used.

these are examples of unused values but they
all seem to be innocent