user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/options/linux/generic/sys-eventfd.cpp

@@ -0,0 +1,45 @@
+#include <sys/eventfd.h>
+#include <errno.h>
+
+#include <bits/ensure.h>
+#include <mlibc/linux-sysdeps.hpp>
+
+int eventfd(unsigned int initval, int flags) {
+	int fd = 0;
+
+	MLIBC_CHECK_OR_ENOSYS(mlibc::sys_eventfd_create, -1);
+	if (int e = mlibc::sys_eventfd_create(initval, flags, &fd); e) {
+		errno = e;
+		return -1;
+	}
+
+	return fd;
+}
+
+int eventfd_read(int fd, eventfd_t *value) {
+	ssize_t bytes_read;
+	if (int e = mlibc::sys_read(fd, value, 8, &bytes_read); e) {
+		errno = e;
+		return -1;
+	}
+
+	if (bytes_read != 8) {
+		return -1;
+	}
+
+	return 0;
+}
+
+int eventfd_write(int fd, eventfd_t value) {
+	ssize_t bytes_written;
+	if (int e = mlibc::sys_write(fd, &value, 8, &bytes_written); e) {
+		errno = e;
+		return -1;
+	}
+
+	if (bytes_written != 8) {
+		return -1;
+	}
+
+	return 0;
+}