Issue #103: allow Infinity and -Infinity to be parsed.
diff --git a/math_compat.h b/math_compat.h
index d94a4da..f40b8fa 100644
--- a/math_compat.h
+++ b/math_compat.h
@@ -21,4 +21,8 @@
 #error This platform does not have nan()
 #endif
 
+#ifndef HAVE_DECL_INFINITY
+#error This platform does not have INFINITY
+#endif
+
 #endif