RISC-V: Moved syscalls to separate files to fix aliasing problems.

libgloss/riscv/sys_isatty.c

@@ -0,0 +1,17 @@
+#include <machine/syscall.h>
+#include <sys/stat.h>
+#include "internal_syscall.h"
+
+extern int _fstat(int file, struct stat *st);
+
+/* Query whether output stream is a terminal. For consistency with the
+   other minimal implementations, which only support output to stdout,
+   this minimal implementation is suggested by the newlib docs.  */
+
+int
+_isatty(int file)
+{
+  struct stat s;
+  int ret = _fstat (file, &s);
+  return ret == -1 ? -1 : !!(s.st_mode & S_IFCHR);
+}