In the non-Windows code paths:
- New approach to compute TZA without the need for GNU-specific
`struct tm.tm_gmtoff`.
- Always using `usleep` to sleep. (No real need for `nanosleep` as
port API has sleep granularity of milliseconds.)
- Not checking for "time.h" at build configuration time as that
header is mandated by the C standard.
- Not checking for "unistd.h" at build configuration time as that
header is mandated by the POSIX standard (the default port is
targeting POSIX systems -- and Windows).
- Fixing some macro guards.
JerryScript-DCO-1.0-Signed-off-by: Akos Kiss [email protected]