Don't foward declare containers when using gcc's parallel library and

add a macro to disable forward declaration. Fixes #3866.

[SVN r59282]

libs/detail

@@ -1 +1 @@
-Subproject commit c2192c4cafaecc6f7125c207d35154f03c650835
+Subproject commit 00e723fba0177e9af660d854e22b6afd3774c273

libs/functional

@@ -1 +1 @@
-Subproject commit 828a9c862c38286cf1eb659a30757acd23b3a307
+Subproject commit d6e254a03bc9fc68660405f689c35d86766749c3