BUILD/MEDIUM: standard: get rid of the last strcpy()

BUILD/MEDIUM: standard: get rid of the last strcpy()

OpenBSD complains about our use of strcpy() in standard.c. The checks
were OK and we didn't fall into the category of "almost always misused",
but it's very simple to fix it so better do it before a problem happens.

src/standard.o(.text+0x26ab): In function `str2sa_range':
src/standard.c:718: warning: strcpy() is almost always misused, please use strlcpy()