The AC_PROG_CC/CXX are searching for a compiler. Will the found compiler being used to compile the feature tests? E.g.: does AC_CHECK_HEADER(...) use the compiler determined by AC_PROG_CC?
What about when the user supplies a compiler via `./configure CC=mygcc'; is that compiler used instead of the compiler found by AC_PROG_CC/CXX? If not what can I do to make the macros use the user supplied compiler? /FAU
