Merge pull request #489 from spevans/pr_install_dispatch_stubs

Install libDispatchStubs.a if building static libraries.

Signed-off-by: Kim Topley <ktopley@apple.com>

Author: ktopley-apple

PATCHES

@@ -501,3 +501,4 @@ github commits starting with 29bdc2f from
 [37010f0] APPLIED rdar://54572081
 [251dba4] APPLIED rdar://54572081
 [a18aa1f] APPLIED rdar://54572081
+[e8d020e] APPLIED rdar://54572081