+dnl ** what are the sizes of various types
+dnl (these must come before GHC_CHECK_ALIGNMENT)
+AC_CHECK_SIZEOF(unsigned int,4)
+AC_CHECK_SIZEOF(float,4)
+AC_CHECK_SIZEOF(double,8)
+
+dnl ** what are alignment constraints on various types
+GHC_CHECK_ALIGNMENT(unsigned int) dnl redundant but harmless
+GHC_CHECK_ALIGNMENT(float)
+GHC_CHECK_ALIGNMENT(double)
+