[Runtime] Add metadata for Builtin.Int7

Fixes rdar://problem/45880755.

Author: DougGregor

docs/ABI/Mangling.rst

@@ -195,8 +195,8 @@ types where the metadata itself has unknown layout.)
   global ::= protocol 'TL'               // protocol requirements base descriptor
   global ::= assoc-type-name 'Tl'        // associated type descriptor
   global ::= assoc-type-name 'TM'        // default associated type witness accessor (HISTORICAL)
-  global ::= type assoc-type-path protocol 'Tn' // associated conformance descriptor
-  global ::= type assoc-type-path protocol 'TN' // default associated conformance witness accessor
+  global ::= type assoc-type-list protocol 'Tn' // associated conformance descriptor
+  global ::= type assoc-type-list protocol 'TN' // default associated conformance witness accessor
 
   REABSTRACT-THUNK-TYPE ::= 'R'          // reabstraction thunk helper function
   REABSTRACT-THUNK-TYPE ::= 'r'          // reabstraction thunk

include/swift/Runtime/BuiltinTypes.def

@@ -33,6 +33,7 @@
 #endif
 
 BUILTIN_TYPE(Bi1_, "Builtin.Int1")
+BUILTIN_TYPE(Bi7_, "Builtin.Int7")
 BUILTIN_TYPE(Bi8_, "Builtin.Int8")
 BUILTIN_TYPE(Bi16_, "Builtin.Int16")
 BUILTIN_TYPE(Bi32_, "Builtin.Int32")

stdlib/public/runtime/KnownMetadata.cpp

@@ -57,6 +57,7 @@ namespace ctypes {
     // Type definitions that map each names Swift builtin type to their
     // C counterparts.
     using Bi1_ = uint8_t;
+    using Bi7_ = uint8_t;
     using Bi8_ = uint8_t;
     using Bi16_ = uint16_t;
     using Bi32_ = uint32_t;