Drop usage of obsolete macros AC_EXEEXT and AC_OBJEXT. * tests/ansi4.test: Drop AC_OBJEXT and AC_EXEEXT. * tests/ansi6.test: Likewise. * tests/ansi7.test: Likewise. * tests/condlib.test: Likewise. * tests/cygwin32.test: Likewise. * tests/exeext2.test: Likewise. * tests/libobj11.test: Likewise. * tests/library.test: Likewise. * tests/txinfo5.test: Likewise. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>