Introduce an 'external_source_symbol' attribute that describes the origin
and the nature of a declaration

This commit adds an external_source_symbol attribute to Clang. This attribute
specifies that a declaration originates from an external source and describes
the nature of that source. This attribute will be used to improve IDE features
like 'jump-to-definition' for mixed-language projects or project that use
auto-generated code.


Differential Revision:

git-svn-id: 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 76f5d5795d4874977a05149b2250c2c30062a723)
15 files changed