[Bug c++/84744] cannot use glibc 2.27 with gcc 7.3

[development@faf-ltd.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84744

--- Comment #10 from Peter VARGA <development@faf-ltd.com> ---
(In reply to Jonathan Wakely from comment #8)
> You need to recompile gcc telling it to use the new glibc.
> 
> When GCC is built it creates fixed dependencies on the C library. You can't
> just point it to a new libc and expect it to work. A new C library needs a
> new compiler as well.
> 
> So build GCC (see https://gcc.gnu.org/wiki/InstallingGCC for a starting
> point) and add --with-native-system-header-dir=/FaF/glibc/include/ to the
> configure options.

The option --with-native-system-header-dir=/FaF/glibc/include/ didn't work.
Now, the include errors appear while compiling gcc.

Below some extract.

I am working on SLES 12 SP3 - the system glibc version is 2.22. OK it is 3
years old.
I am using the newest glibc version 2.27 only for my project.

The question is if I really need the newest version. It makes the whole process
only too complicated.


--------------------------------------------------------------------------------
In file included from /FaF/glibc/include/errno.h:28:0,
                 from ../../../gcc-7.3.0/libgcc/../gcc/tsystem.h:93,
                 from ../../../gcc-7.3.0/libgcc/libgcc2.c:27:
/FaF/glibc/include/bits/errno.h:26:11: fatal error: linux/errno.h: No such file
or directory
 # include <linux/errno.h>
           ^~~~~~~~~~~~~~~
In file included from /FaF/glibc/include/errno.h:28:0,
                 from ../../../gcc-7.3.0/libgcc/../gcc/tsystem.h:93,
                 from ../../../gcc-7.3.0/libgcc/libgcov.h:42,
                 from ../../../gcc-7.3.0/libgcc/libgcov-interface.c:26:
/FaF/glibc/include/bits/errno.h:26:11: fatal error: linux/errno.h: No such file
or directory
 # include <linux/errno.h>
           ^~~~~~~~~~~~~~~
In file included from /FaF/glibc/include/errno.h:28:0,
                 from ../../../gcc-7.3.0/libgcc/../gcc/tsystem.h:93,
                 from ../../../gcc-7.3.0/libgcc/libgcov.h:42,
                 from ../../../gcc-7.3.0/libgcc/libgcov-merge.c:26: