Workaround for real_concept when there are no long double math functions.

Added HP-UX on PA RISC to list of platforms with no long double overloads.
Added macro expansion suppression code to declarations of sign and to it's usages (an AIX fix).

[SVN r40155]

libs/math

@@ -1 +1 @@
-Subproject commit 5aaa44f9011cfe81882309fc040caab52d5c689f
+Subproject commit 82eb0636b92c7ab78bf17590232bbb465e434b5a