diff --git a/configure.ac b/configure.ac
index 37d9d75..aa8a16e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -283,6 +283,18 @@
 fi
 AM_CONDITIONAL(WITH_TESTS, [test "$have_tests" = "yes"])
 
+AM_CONDITIONAL(MINGW, false)
+case "${host_os}" in
+*mingw*)
+  mingw32_support="yes"
+  AC_CHECK_HEADER(windows.h)
+  AM_CONDITIONAL(MINGW, true)
+  ;;
+*)
+  AC_ISC_POSIX
+  ;;
+esac
+
 AC_C_CONST
 AC_C_INLINE
 AC_C_VOLATILE