Project:Toolchain/Glibc 2.28 porting notes/libio h removal

From the release notes: installed. Software that was using either header should be updated to use standard  interfaces instead.
 * The nonstandard header files  and <_G_config.h> are no longer

This leads apparently to some side effects. In particular, stdio.h did previously include abovementioned libio.h, which unintentionally leaked the complete definition of struct FILE.

A workaround for software that now fails to build is to additionally #include  (but keep in mind that this header was only added in 2.28, and doesnt exist in previous glibc versions).

glibc commit: a4fea3f2c3253b9ae6ffacd3747034ccbe56bc60