Make libasyncio headers usable from C

This allows us to enable LTP tests
for io_* syscalls.

Bug: 31152298
Test: LTP tests pass
Change-Id: Ic25189d8bf25cdacfa0f144ac57c7b2827adcd9f
diff --git a/libasyncio/AsyncIO.cpp b/libasyncio/AsyncIO.cpp
index 7430bc8..6149f09 100644
--- a/libasyncio/AsyncIO.cpp
+++ b/libasyncio/AsyncIO.cpp
@@ -17,9 +17,10 @@
 #include <asyncio/AsyncIO.h>
 #include <sys/syscall.h>
 #include <unistd.h>
+#include <cstdint>
+#include <cstring>
 
 int io_setup(unsigned nr, aio_context_t* ctxp) {
-    memset(ctxp, 0, sizeof(*ctxp));
     return syscall(__NR_io_setup, nr, ctxp);
 }
 
@@ -48,3 +49,11 @@
     iocb->aio_nbytes = count;
     iocb->aio_offset = offset;
 }
+
+void io_prep_pread(struct iocb* iocb, int fd, void* buf, size_t count, long long offset) {
+    io_prep(iocb, fd, buf, count, offset, true);
+}
+
+void io_prep_pwrite(struct iocb* iocb, int fd, void* buf, size_t count, long long offset) {
+    io_prep(iocb, fd, buf, count, offset, false);
+}