see build https://koji.fedoraproject.org/koji/taskinfo?taskID=36304162
These are the relevant lines in the build log:
BUILDSTDERR: ../../mono/utils/mono-sigcontext.h:416:63: error: 'struct sigcontext' has no member named 'arm_sp'
BUILDSTDERR: 416 | #define UCONTEXT_REG_SP(ctx) (((arm_ucontext*)(ctx))->sig_ctx.arm_sp)
Seems it builds now in Rawhide without changes, according to Koschei.
I will close the bug on Monday, if the build succeeds.
It seems something outside of Mono was broken in Rawhide, it is working again.