RISCV64: "xflag not define" cause compile failure

Created by: shiptux

Describe the bug The DynamoRIO lib that is built using GCC on a QEMU-RISCV64 machine. Report this error: ‘dr_mcontext_t’ {aka ‘struct _dr_mcontext_t’} has no member named ‘xflags’;

To Reproduce

Compiling DynamoRIO under RISCV64 QEMU or machine
cmake ../ && make -j

Expected behavior DynamoRIO should be able to compile correctly under RISCV64

Screenshots or Pasted Text If applicable, add screenshots to help explain your problem. For text, please cut and paste the text here, delimited by lines consisting of three backtics to render it verbatim, like this:

```
[ 72%] Building C object ext/drbbdup/CMakeFiles/drbbdup.dir/drbbdup.c.o
/root/dynamorio/ext/drbbdup/drbbdup.c: In function ‘drbbdup_event_restore_state’:
/root/dynamorio/ext/drbbdup/drbbdup.c:2195:49: error: ‘dr_mcontext_t’ {aka ‘struct _dr_mcontext_t’} has no member named ‘xflags’; did you mean ‘flags’?
 2195 |                     reg_t cur = info->mcontext->xflags;
      |                                                 ^~~~~~
      |                                                 flags
```

Versions

What version of DynamoRIO are you using? The latest version from DynamoRIO upstream.
Does the latest build from https://github.com/DynamoRIO/dynamorio/releases solve the problem? No
What operating system version are you running on? ("Windows 10" is not sufficient: give the release number.) Debian QEMU RISCV64