lib: Add RISC-V64 Linux syscall numbers header.

* include/linux/riscv64/syscall.h: New file: list relevant syscall
number constants.

include/linux/riscv64/syscall.h

@@ -0,0 +1,96 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __MES_LINUX_RISCV_SYSCALL_H
+#define __MES_LINUX_RISCV_SYSCALL_H 1
+
+/** RISC-V uses the asm-generic syscalls (asm-generic/unistd.h) with the
+    following configuration for 64-bit:
+ * #define __ARCH_WANT_NEW_STAT
+ * #define __ARCH_WANT_SET_GET_RLIMIT
+ * #define __ARCH_WANT_SYS_CLONE3
+ */
+
+// libc-mini
+#ifndef SYS_exit
+#define SYS_exit        93
+#endif
+#ifndef SYS_write
+#define SYS_write       64
+#endif
+
+// libc
+#define SYS_clone          220
+#define SYS_read           63
+#define SYS_openat         56
+#define SYS_wait4          260
+#define SYS_execve         221
+#define SYS_fchmodat       53
+#define SYS_faccessat      48
+#define SYS_brk            214
+#define SYS_ioctl          29
+#define SYS_fsync          82
+
+// libc+tcc
+#define SYS_close          57
+#define SYS_lseek          62
+#define SYS_unlinkat       35
+#define SYS_gettimeofday   169
+#define SYS_getcwd         17
+
+// libc+gnu
+
+#define SYS_chdir          49
+#define SYS_linkat         37
+#define SYS_getpid         172
+#define SYS_getuid         174
+#define SYS_kill           129
+#define SYS_renameat2      276
+#define SYS_mkdirat        34
+#define SYS_dup            23
+#define SYS_pipe2          59
+#define SYS_getgid         176
+#define SYS_rt_sigaction   134
+#define SYS_fcntl          25
+#define SYS_dup3           24
+#define SYS_getrusage      165
+#define SYS_newfstatat     79
+#define SYS_setitimer      103
+#define SYS_fstat          80
+#define SYS_nanosleep      101
+#define SYS_getdents64     61
+#define SYS_clock_gettime  113
+
+// bash
+#define SYS_setuid         146
+#define SYS_geteuid        175
+#define SYS_getegid        177
+#define SYS_setgid         144
+#define SYS_getppid        173
+
+// make+POSIX
+#define SYS_rt_sigprocmask 135
+
+// tar
+#define SYS_symlinkat      36
+#define SYS_readlinkat     78
+#define SYS_mknodat        33
+
+#endif // __MES_LINUX_RISCV_SYSCALL_H