[Bug bootstrap/61388] [4.8 Regression] linux/microblaze fails to build: undefined machine-specific constraint at this point: "Q"

[eager at eagercon dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61388

--- Comment #3 from Michael Eager <eager at eagercon dot com> ---
What sources are you building?  

When I build --target=microblaze-xilinx-elf from the current sources, I see the
same warning message for microblaze.md that you list.  I do not see the other
errors.  Constraint "Q" is defined in constraints.md.