www/receiptomatic-www: Fix a compiler warning in set_proc_title()
www/receiptomatic-www: Fix a compiler warning in set_proc_title()

When compiling with GCC 9.2.1 under Fedora 31 I got the following
compiler warning

  CC	receiptomatic-www.o
In file included from /usr/include/string.h:495,
                 from receiptomatic-www.c:18:
In function ‘strncpy’,
    inlined from ‘set_proc_title’ at receiptomatic-www.c:119:4:
/usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
  106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
receiptomatic-www.c: In function ‘set_proc_title’:
receiptomatic-www.c:116:11: note: length computed here
  116 |    size = strlen(environ[i]) + 1;
      |           ^~~~~~~~~~~~~~~~~~

Replace the strncpy(3) that copies the above environ[i] (+ nul byte)
into a new area with a memcpy(3). I don;t the think the strncpy(3) was
wrong per se, but given str[n]cpy(3)'s various behaviours, memcpy() is
probably a better choice.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@digital-domain.net>

ac000/receiptomatic