Add a missing(?) typedef, don't use using with mwcw, try comeau with c99 fenv

[SVN r18604]

libs/numeric/interval

@@ -1 +1 @@
-Subproject commit 3539db967f1a3e65eebbd03e2c754a4a423fb6e9
+Subproject commit 6a800aa4ab897889bb28f8f6d764813efe5f60d0