Hi Mathieu,

Thanks for reporting this.

This appears to be an upstream GDB issue affecting musl builds. The failure comes from set_custom_baudrate_linux() in gdb/ser-unix.c, which directly accesses struct termios members c_ospeed / c_ispeed. These fields exist with those names in glibc, but musl exposes them as __c_ospeed / __c_ispeed, which explains the build breakage you’re seeing.

There is an upstream Bugzilla report tracking this issue:
https://sourceware.org/bugzilla/show_bug.cgi?id=33747

I’ve been participating in the discussion there and shared some investigation and a possible direction, but there is no agreed-upon fix yet. A few important points from the upstream discussion so far:

• Simply switching to cfset[io]speed() is not sufficient in all cases, since musl rejects non-standard baud rates and the existing GDB code intentionally bypasses that API.

• Using libc-specific field names via #ifdef is fragile.

• One possible approach under discussion is using a Linux termios2-based path guarded by TCGETS2, but this needs careful handling (e.g. BOTHER values differ across architectures).

Given this, it seems best to let this get resolved upstream rather than adding a temporary OE-Core workaround. I’ll keep an eye on the upstream bug and follow up once there’s either a merged fix or a clearly recommended approach we can backport.

Thanks,
Sunil