Or else the installed rustc and cargo use /lib64/ld-linux-x86-64.so.2
How exactly did you patch it? I'm hitting the same issue in my centos 7 prefix
From the comment by OP, I suspect he changed INTERP to point to the prefix-baed one. Probably something like patchelf --set-interpreter $EPREFIX/lib/ld-linux-*.so.* $EPREFIX/usr/bin/rust
I have reproduced this bug.
*** This bug has been marked as a duplicate of bug 682370 ***