SQLite has an SQLITE_OS_* directive for each
operating system it natively supports. Normally, SQLite will try
to determine what operating system it is running on by examining
various automatic compiler
directives. If you’re cross-compiling, you can manually
set SQLITE_OS_OTHER to 1. This will override all other
SQLITE_OS_* flags and
disable the default operating system interfaces. This directive
is mainly of interest to people working on embedded
systems.