RFC: remove the "tile" architecture from glibc

[Joseph Myers]

On Thu, 1 Feb 2018, Adhemerval Zanella wrote:

> Trying to build/run glibc testsuite against sh4 own toolchain I am facing
> an build issue for some tests:
> 
> ---
> gcc -nostdlib -nostartfiles -o /home/azanella/glibc/glibc-git-build/assert/tst-assert-c++    -Wl,-z,combreloc -Wl,-z,relro -Wl,--hash-style=both /home/azanella/glibc/glibc-git-build/csu/crt1.o /home/azanella/glibc/glibc-git-build/csu/crti.o `gcc  --print-file-name=crtbegin.o` /home/azanella/glibc/glibc-git-build/assert/tst-assert-c++.o /home/azanella/glibc/glibc-git-build/support/libsupport_nonshared.a -lstdc++ -Wl,-dynamic-linker=/lib/ld-linux.so.2 -Wl,-rpath-link=/home/azanella/glibc/glibc-git-build:/home/azanella/glibc/glibc-git-build/math:/home/azanella/glibc/glibc-git-build/elf:/home/azanella/glibc/glibc-git-build/dlfcn:/home/azanella/glibc/glibc-git-build/nss:/home/azanella/glibc/glibc-git-build/nis:/home/azanella/glibc/glibc-git-build/rt:/home/azanella/glibc/glibc-git-build/resolv:/home/azanella/glibc/glibc-git-build/crypt:/home/azanella/glibc/glibc-git-build/mathvec:/home/azanella/glibc/glibc-git-build/support:/home/azanella/glibc/glibc-git-build/nptl /home/azanella/glibc/glibc-git-build/libc.so.6 /home/azanella/glibc/glibc-git-build/libc_nonshared.a -Wl,--as-needed /home/azanella/glibc/glibc-git-build/elf/ld.so -Wl,--no-as-needed -lgcc -Wl,--as-needed -lgcc_s  -Wl,--no-as-needed `gcc  --print-file-name=crtend.o` /home/azanella/glibc/glibc-git-build/csu/crtn.o
> /usr/lib/gcc/sh4-linux-gnu/7/libgcc_s.so.1: undefined reference to `__fpscr_values@GLIBC_2.2'
> collect2: error: ld returned 1 exit status

I think some distributions have a local glibc patch related to 
__fpscr_values, so a newly built glibc may be ABI-incompatible with 
binaries built against such a patched glibc.  (The use of __fpscr_values 
is fundamentally flawed, but that was supposed to be fixed for GCC 5 - see 
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53513> and its duplicate 
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60138>.)

-- 
Joseph S. Myers
joseph@codesourcery.com