Detect gcc stdlib for gcc 4.0.1.

For some reason the normal macros aren't defined for the standard
library that comes with gcc 4.0.1 (although maybe just on BSDs?). So try
to detect the library for that compiler.

[SVN r52245]

libs/detail

@@ -1 +1 @@
-Subproject commit de4c1b2e9d003cb5f6b54360dfd7fef96b3fd620
+Subproject commit 3178938f98f5627fd800b392dc717ec596659847

libs/functional

@@ -1 +1 @@
-Subproject commit e5e7db003d8222caad39d5ef96dd3f31cd938e70
+Subproject commit 18c9f2a435dd85aca59fe504c11399a1d0157e67