Add configure script

Some older installs don't have __kernel_rwf_t in linux/fs.h, so
add a check for that.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

src/compat.h

@@ -0,0 +1,8 @@
+#ifndef LIBURING_COMPAT_H
+#define LIBURING_COMPAT_H
+
+#if !defined(CONFIG_HAVE_KERNEL_RWF_T)
+typedef int __kernel_rwf_t;
+#endif
+
+#endif

src/io_uring.c

@@ -5,6 +5,7 @@
 #include <errno.h>
 #include <string.h>
 
+#include "compat.h"
 #include "io_uring.h"
 #include "liburing.h"
 #include "barrier.h"

src/liburing.h

@@ -2,6 +2,7 @@
 #define LIB_URING_H
 
 #include <sys/uio.h>
+#include "compat.h"
 #include "io_uring.h"
 
 /*

src/syscall.c

@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <sys/syscall.h>
 #include <sys/uio.h>
+#include "compat.h"
 #include "io_uring.h"
 
 #if defined(__x86_64)