When running cpp -v I do get the following output:

(...)
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc-lib/i386-redhat-linux/2.96/include
 /usr/include
End of search list.
^C

Hm, I do understand why /usr/local/include is here,
but why /usr/i386-redhat-linux/include? Bug?