The current glibc ebuild runs some simple tests at the end of the build procedure to verify the build went fine. (line 497 and on it glibc-2.3.5.ebuild) These test fail when cross-compiling glibc because it's obvious I cannot run the target-system binaries. Also, the lines 540-544 don't make much sense on a cross-compiled system and should be executed conditionally only if ${ROOT}="/"
a cross-compiling setup will never reach the simple sanity checks ive fixed the iconv stuff in the latest 3 ebuilds
Let's take a deeper look into the ebuild. The native tests should be skipped when is_crosscompile() returns true. is_crosscompile returns true if CHOST and CTARGET (which is previously taken from CHOST) differ. When cross-compiling a native build (to be used on other system) CHOST = CTARGET! See http://podgorny.cz/moin/GentooOnIpaq how to reproduce...
again, this is because you didnt provide enough info off the bat :p
added a CBUILD!=CHOST check before doing the ld-* tests