libsanitizer requires wordexp. Therefore gcc has to be configured with --disable-libsanitizer if uclibc is configured without UCLIBC_HAS_WORDEXP.
By default, UCLIBC_HAS_WORDEXP is disabled.
As a workaround, you can use package.env to disable libsanitizer for all uclibc toolchains:
i've made the sanitizer library a USE=sanitize flag. you can disable that when your C library setup lacks functionality it needs.
I don't think it makes a good default:
+ tc_version_is_at_least 4.8 && IUSE_DEF+=( sanitize )
*** This bug has been marked as a duplicate of bug 504200 ***