Define I386_USE_SYSENTER to 0 or 1 so that special versions of syscalls
with "int $0x80" can be provided for static PIE during self relocation.
Also check PIC instead SHARED for PIC version of syscall macros.
* sysdeps/unix/sysv/linux/i386/sysdep.h (I386_USE_SYSENTER):
Define to I386_USE_SYSENTER to 0 or 1 if not defined.
(ENTER_KERNEL): Check if I386_USE_SYSENTER is 1 and check PIC.
(INTERNAL_SYSCALL_MAIN_INLINE): Likewise.
(INTERNAL_SYSCALL_NCS): Likewise.
(LOADARGS_1): Likewise.
(LOADARGS_5): Likewise.
(RESTOREARGS_1): Likewise.
(RESTOREARGS_5): Likewise.