buildsys: Fix kbuild-style switch fallout

regressions introduced in 1b3025b7352f5e432ffa1c7adc57085ac9092b77
"buildsys: switch libc to kbuild-style"

unistd: Handle !UCLIBC_HAS_GET{, SUB}OPT cases

libc/libc_so.a(getsubopt-susv3.os): In function getsubopt':
getsubopt-susv3.c:(.text+0x0): multiple definition of getsubopt'
libc/libc_so.a(getsubopt.os):getsubopt.c:(.text+0x0):
first defined here.

The solution is to filter out the correct files when
UCLIBC_HAS_GETOPT and UCLIBC_HAS_GETSUBOPT are not defined.

inet: Move INET_RPC_{DIR, OUT} before CSRC_ALL

libc/libc_so.a(rpc_thread.oS): In function __rpc_thread_svc_max_pollfd':
rpc_thread.c:(.text+0x148): undefined reference to svc_max_pollfd'
libc/libc_so.a(rpc_thread.oS): In function __rpc_thread_svc_pollfd':
rpc_thread.c:(.text+0x184): undefined reference to svc_pollfd'

The CSRC_ALL variable uses the INET_RPC_DIR variable which is
initialized later on. We fix this problem by moving the
INET_RCP_{DIR,OUT} definitions before we use them in CSRC_ALL

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
buildsys: switch warning into a TODO

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>