Errors cross-compiling gdbserver with glibc-2.34

[Chris Packham]

Hi,

I'm looking at updating crosstool-ng to add glibc-2.34. I can generate a 
toolchain fine but when I try to build gdbserver (which can be enabled 
as part of the crosstool-ng build) I get some odd gnulib build errors.

https://github.com/crosstool-ng/crosstool-ng/pull/1570#issuecomment-893784531

I can disable building gdbserver as part of crosstool-ng and 
successfully generate a toolchain. But when I use that toolchain to 
manually build gdbserver I get the same error (included below as it has 
a bit more useful output than on the link above).

   CXX    amd64-linux-siginfo.o
In file included from 
/home/ctng/x-tools/x86_64-unknown-linux-gnu/x86_64-unknown-linux-gnu/sysroot/usr/include/bits/sigstksz.h:24,
                  from 
/home/ctng/x-tools/x86_64-unknown-linux-gnu/x86_64-unknown-linux-gnu/sysroot/usr/include/signal.h:328,
                  from build-gnulib-gdbserver/import/signal.h:52,
                  from 
../../../gdb-9.2/gdb/gdbserver/../nat/amd64-linux-siginfo.c:20:
build-gnulib-gdbserver/import/unistd.h:135:3: error: #error "Please 
include config.h first."
   135 |  #error "Please include config.h first."
       |   ^~~~~
In file included from 
/home/ctng/x-tools/x86_64-unknown-linux-gnu/x86_64-unknown-linux-gnu/sysroot/usr/include/bits/sigstksz.h:24,
                  from 
/home/ctng/x-tools/x86_64-unknown-linux-gnu/x86_64-unknown-linux-gnu/sysroot/usr/include/signal.h:328,
                  from build-gnulib-gdbserver/import/signal.h:52,
                  from 
../../../gdb-9.2/gdb/gdbserver/../nat/amd64-linux-siginfo.c:20:
build-gnulib-gdbserver/import/unistd.h:137:1: error: 
'_GL_INLINE_HEADER_BEGIN' does not name a type
   137 | _GL_INLINE_HEADER_BEGIN
       | ^~~~~~~~~~~~~~~~~~~~~~~
build-gnulib-gdbserver/import/unistd.h:1929:1: error: 
'_GL_INLINE_HEADER_END' does not name a type
  1929 | _GL_INLINE_HEADER_END
       | ^~~~~~~~~~~~~~~~~~~~~
make: *** [Makefile:635: amd64-linux-siginfo.o] Error 1

Everything works fine with the same configuration under glibc-2.33.

Any clues as to what might be going on? I'm kind of thinking there must 
be some difference in include paths between glibc-2.33 and glibc-2.34.

Thanks,
Chris