[Bug bootstrap/77661] --enable-maintainer-mode causes in-tree-build of MPC to fail

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77661

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Does adding --disable-maintainer-mode to Makefile.def extra_configure_flags for
MPC help?