bsd.own.mk: rename GCC_NO_* to CC_WNO_*

Rename compiler-warning-disable variables from
GCC_NO_warning
to
CC_WNO_warning
where warning is the full warning name as used by the compiler.

GCC_NO_IMPLICIT_FALLTHRU is CC_WNO_IMPLICIT_FALLTHROUGH

Using the convention CC_compilerflag, where compilerflag
is based on the full compiler flag name.

introduce some common variables for use in GCC warning disables:

GCC_NO_FORMAT_TRUNCATION -Wno-format-truncation (GCC 7/8)
GCC_NO_STRINGOP_TRUNCATION -Wno-stringop-truncation (GCC 8)
GCC_NO_STRINGOP_OVERFLOW -Wno-stringop-overflow (GCC 8)
GCC_NO_CAST_FUNCTION_TYPE -Wno-cast-function-type (GCC 8)

use these to turn off warnings for most GCC-8 complaints. many
of these are false positives, most of the real bugs are already
commited, or are yet to come.


we plan to introduce versions of (some?) of these that use the
"-Wno-error=" form, which still displays the warnings but does
not make it an error, and all of the above will be re-considered
as either being "fix me" (warning still displayed) or "warning
is wrong."

no -g

Fix another bug found by jemalloc: don't access dirent entry after closedir(3).

branches: 1.1.16;
Add a program to find the latest timestamp in a cvs repository

cvslatest(1): remove RETURN VALUES

Pages in section one should use EXIT STATUS instead (which this one
already provides).

Closes PR 57778 by Kouichi Hashikawa

branches: 1.1.26;
Add a program to find the latest timestamp in a cvs repository

simplify previous

While this is not intended to be used on unclean checkouts, improve
diagnostics if it happens.
Add another variant of a "new entry" dummy timestamp found in the
cvs code (but not seen in checkouts in the wild).

Handle dummy timestamp better and check for I/O errors. From khorben@

Fix another bug found by jemalloc: don't access dirent entry after closedir(3).

branches: 1.7.2;
deal with cvs meta-data directories not called CVS.

branches: 1.6.2;
Force _GNU_SOURCE on Linux, otherwise strptime is not defined and more
restrictive macros result in even nastier fallout.

give the absolute path for the error message.

- use UTC
- initialize tm_isdst
- use accpath to handle relative paths

print only the latest entry for debugging.

branches: 1.2.2;
Toolify

Add a program to find the latest timestamp in a cvs repository