`gcc-sh-elf-newlib` build fails for GCC 10.1

[michalsieron]

CI in #31 revealed, that gcc-newlib-sh-linux step is failing (run#3651807217).

There seems to a problem with duplicate _errno symbols (see line 65617 of logs).

Here it is cleaned up a little bit:

$PREFIX/sh-elf/bin/ld:
  $PREFIX/sh-elf/lib/libc.a(lib_a-syscalls.o):(.bss+0x0): multiple definition of `_errno';
  $PREFIX/sh-elf/lib/libc.a(lib_a-reent.o):(.bss+0x0): first defined here

Below is a comparison of *_errno symbols in newlib libc compiled with GCC 9.2 and GCC 10.1:

$ # GCC 9.2
$ sh-elf-nm -g sh-elf/lib/libc.a | grep _errno | sort | uniq -c
     20          U ___errno
     17          U _errno
      1 00000000 T ___errno
      2 00000004 C _errno

$ # GCC 10.1
$ sh-elf-nm -g sh-elf/lib/libc.a | grep _errno | sort | uniq -c
     20          U ___errno
     17          U _errno
      2 00000000 B _errno
      1 00000000 T ___errno

Looks like _errnos are in BSS and not in COMMON section.

I'm pretty confident, that this is a reason: https://wiki.gentoo.org/wiki/Project:Toolchain/Gcc_10_porting_notes/fno_common

Although neither adding CFLAGS=-fcommon in make call or before configure seems to help.

For this reason we skip the gcc-sh-elf-newlib-linux for now, but it needs to be repaired.

[mithro]

@cr1901 -- Any ideas?

[cr1901]

@mithro No, I've never seen this error before, and I would expect adding -fcommon to CFLAGS would fix it. This might require a dive into the autotools machinery to figure out why -fcommon isn't being honored.

Did you do a make distclean before adding the new flags?