* configure.in: detect cygwin* instead of cygwin32*

  	* configure: regenerate
  	* configure.in: in comment, call AC_EXEEXT instead of AM_EXEEXT


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@23725 138bc75d-0d04-0410-961f-82ee72b054a4