consider including own glibc in toolchains

[boegel]

Some useful info on this I just ran into: https://stackoverflow.com/questions/847179/multiple-glibc-libraries-on-a-single-host/851229#851229

[bartoldeman]

See also the prefix-standalone method used by Gentoo prefix: https://wiki.gentoo.org/wiki/Project:Prefix/Technical_Documentation#Search_pathes

The main thing to consider is that you cannot set LD_LIBRARY_PATH to a 2nd glibc as that breaks system binaries such as /bin/bash. You can set the path using rpath, or probably more naturally by using the dynamic loader e.g. ld-linux-x86-64.so.2 that comes with that glibc, and uses its prefix instead of /lib64 or /usr/lib64 to search for libraries as the last place to look.

Note that glibc can be compiled using user-defined-trusted-dirs=... as a make flag to define additional search paths for shared libraries. Note trusted here comes from the fact they are considered by suid binaries too, which ignore LD_LIBRARY_PATH. Such default dirs are also then considered for indirect library dependencies, like RPATH but unlike RUNPATH.