5.10 Compilers and Preprocessors

All the tests for compilers (AC_PROG_CC, AC_PROG_CXX, AC_PROG_F77) define the output variable EXEEXT based on the output of the compiler, typically to the empty string if Posix and ‘.exe’ if a DOS variant.

They also define the output variable OBJEXT based on the output of the compiler, after ‘.c’ files have been excluded, typically to ‘o’ if Posix, ‘obj’ if a DOS variant.

If the compiler being used does not produce executables, the tests fail. If the executables can't be run, and cross-compilation is not enabled, they fail too. See section Manual Configuration, for more on support for cross compiling.