Add helpers include file

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.h b/fio.h
index 1723067..214fbd2 100644
--- a/fio.h
+++ b/fio.h
@@ -29,6 +29,7 @@
 #include "ioengine.h"
 #include "iolog.h"
 #include "profiles.h"
+#include "helpers.h"
 
 #ifdef FIO_HAVE_GUASI
 #include <guasi.h>
diff --git a/helpers.c b/helpers.c
index 21b9913..f314ebb 100644
--- a/helpers.c
+++ b/helpers.c
@@ -1,6 +1,8 @@
 #include <malloc.h>
 #include <stdlib.h>
 #include <errno.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
 
 #include "compiler/compiler.h"
 
@@ -17,3 +19,8 @@
 {
 	return 0;
 }
+
+int __weak inet_aton(const char *cp, struct in_addr *inp)
+{
+	return 0;
+}
diff --git a/helpers.h b/helpers.h
new file mode 100644
index 0000000..a3a773b
--- /dev/null
+++ b/helpers.h
@@ -0,0 +1,10 @@
+#ifndef FIO_HELPERS_H
+#define FIO_HELPERS_H
+
+struct in_addr;
+
+extern int __weak posix_memalign(void **ptr, size_t align, size_t size);
+extern int __weak posix_fallocate(int fd, off_t offset, off_t len);
+extern int __weak inet_aton(const char *cp, struct in_addr *inp);
+
+#endif