Make cvs-head gdbserver get error

[Hui Zhu]

gcc -c  -Wall -g    -I. -I../../../src/gdb/gdbserver
-I../../../src/gdb/gdbserver/../common
-I../../../src/gdb/gdbserver/../regformats
-I../../../src/gdb/gdbserver/../../include
../../../src/gdb/gdbserver/linux-low.c -DUSE_THREAD_DB
../../../src/gdb/gdbserver/linux-low.c: In function
'usr_store_inferior_registers':
../../../src/gdb/gdbserver/linux-low.c:2011: error: 'pid' undeclared
(first use in this function)
../../../src/gdb/gdbserver/linux-low.c:2011: error: (Each undeclared
identifier is reported only once
../../../src/gdb/gdbserver/linux-low.c:2011: error: for each function
it appears in.)
make[4]: *** [linux-low.o] Error 1