FROMLIST: select: tests offer choice of syscall path:

Switch between libc library, __newselect syscall, select syscall or
pselect6 syscall for selection of select() tests.  This provides
filled in coverage of all the possible select alternatives.

CC flags can be one of:

-DSYSCALL_SELECT_LIBC        // use select() libc library function
-DSYSCALL_SELECT__NEWSELECT  // use __NR__newselect system call
-DSYSCALL_SELECT_SELECT      // use __NR_select system call
-DSYSCALL_SELECT_PSELECT6    // use __NR_pselect6 system call worker
<default>                    // chose a _defined_ system call

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: kernel-team@android.com
Cc: ltp@lists.linux.it
Bug: 112468806
Change-Id: Ie3c9f1edc217f63184a1532fbbea254415ca90a0
Test: run vts-kernel -m VtsKernelLtp
Signed-off-by: Steve Muckle <smuckle@google.com>