LibC: implement close

libc/stdio.cpp

@@ -52,7 +52,7 @@ char* ctermid(char* buffer)
 
 int fclose(FILE* file)
 {
-	if (syscall(SYS_CLOSE, file->fd) < 0)
+	if (close(file->fd) == -1)
 		return EOF;
 	file->fd = -1;
 	return 0;

libc/unistd.cpp

@@ -187,6 +187,11 @@ long syscall(long syscall, ...)
 	return ret;
 }
 
+int close(int fd)
+{
+	return syscall(SYS_CLOSE, fd);
+}
+
 int execl(const char* pathname, const char* arg0, ...)
 {
 	if (arg0 == nullptr)