llvm-gcc-4.2/gcc/testsuite/gcc.dg/glibc-uclibc-2.c

/* Test -mglibc and -muclibc not allowed together.  */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do link { target *-*-linux* } } */
/* { dg-options "-muclibc -mglibc" } */

/* { dg-error "-mglibc and -muclibc used together" "" { target *-*-* } 0 } */