fcntl.c: use <linux/fcntl.h> instead of <fcntl.h>

fcntl.c: use <linux/fcntl.h> instead of <fcntl.h>

Include <linux/fcntl.h> for proper definitions of F_* constants
and flock structures.

* configure.ac (AC_CHECK_TYPES): Check for struct flock, struct flock64,
struct __kernel_flock, and struct __kernel_flock64 in <linux/fcntl.h>.
* flock.h: New file.
* Makefile.am (strace_SOURCES): Add it.
* fcntl.c: Include it instead of <fcntl.h>.
(struct flock64): Remove.
(printflock): Use struct_kernel_flock instead of struct flock.
(printflock64): Use struct_kernel_flock64 instead of struct flock64.