Generally, the `configure.ac` script tries to detect compilers based on the path to the compiler. This is mostly fine, but trips up when using `mpicc` as the compiler. Even if the underlying compiler is `gcc`, this gets detected as `icc` in various situations.

The best solution is to do some compiler introspection like CMake does to determine what the compiler actually is, but I'm not familiar with the patterns used or available tools in autotools for such things.