dnl
AC_DEFUN([FPTOOLS_HAPPY],
[AC_PATH_PROG(HappyCmd,happy,)
+# Happy is passed to Cabal, so we need a native path
+if test "x$HostPlatform" = "xi386-unknown-mingw32" && \
+ test "${OSTYPE}" != "msys" && \
+ test "${HappyCmd}" != ""
+then
+ # Canonicalise to <drive>:/path/to/gcc
+ HappyCmd=`cygpath -m ${HappyCmd}`
+ AC_MSG_NOTICE([normalized happy command to $HappyCmd])
+fi
+
AC_CACHE_CHECK([for version of happy], fptools_cv_happy_version,
changequote(, )dnl
[if test x"$HappyCmd" != x; then