Fix libgloss and Newlib RISC-V builds for rv64e

The RISC-V E ISA is a reduced integer base ISA available for both rv32
and rv64. The relevant section[1] states:

"RV32E and RV64E reduce the integer register count to 16 general-purpose
registers, (x0-x15), where x0 is a dedicated zero register."

rv64e is ratified,[2] so it's a valid architecture that could be built.
Currently both libgloss and Newlib handle the case for rv32e, but not
rv64e. If you attempt to build for rv64e, it results in a build error
due to accessing registers beyond the first 16. By changing the existing
macro check to __riscv_abi_rve, this will handle both rv32e and rv64e,
since the E ISA requires the use of either the ilp32e or lp64e ABI.

[1] https://github.com/riscv/riscv-isa-manual/blob/e5078e55ea977ef197066dcd3f7c8e09032cb348/src/rv32e.adoc#rv32e-and-rv64e-programmers-model
[2] https://github.com/riscv/riscv-isa-manual/blob/e5078e55ea977ef197066dcd3f7c8e09032cb348/src/colophon.adoc#preface

Eric Salem (2):
  libgloss: riscv: Fix build for rv64e
  newlib: riscv: Fix build for rv64e

 libgloss/riscv/internal_syscall.h  | 2 +-
 newlib/libc/machine/riscv/setjmp.S | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

-- 
2.49.0