[Bug target/90419] New: RISCV --with-multilib-list support is somewhat incomplete

[dilfridge at gentoo dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90419

            Bug ID: 90419
           Summary: RISCV --with-multilib-list support is somewhat
                    incomplete
           Product: gcc
           Version: 8.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dilfridge at gentoo dot org
  Target Milestone: ---

Right now, building a multilib compiler for riscv64 / glibc gives you two
options: 

1) Enable multilib, no further specifications

This tries to build both rv64gc and rv32i, and fails badly because glibc does
not support 32bit yet (it #errors in headers).

2) Use --with-multilib-list, which is restricted to one ABI and thus makes the
whole *multi*lib thing a bit pointless. 


Being able to select more than one ABI, or being able to deselect all of 32bit
(at least until glibc support for that is available) would be highly desirable.