IRGen: Fix Linux build -- non-external functions have protected linkage

Author: slavapestov

test/IRGen/protocol_resilience.sil

@@ -41,7 +41,7 @@ protocol InternalProtocol {
 }
 
 
-// CHECK-LABEL: define void @defaultC(%swift.opaque* noalias nocapture, %swift.type* %Self, i8** %SelfWitnessTable)
+// CHECK-LABEL: define{{( protected)?}} void @defaultC(%swift.opaque* noalias nocapture, %swift.type* %Self, i8** %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 sil @defaultC : $@convention(witness_method) <Self where Self : ResilientProtocol> (@in_guaranteed Self) -> () {
@@ -52,7 +52,7 @@ bb0(%0 : $*Self):
 }
 
 
-// CHECK-LABEL: define void @defaultD(%swift.opaque* noalias nocapture, %swift.type* %Self, i8** %SelfWitnessTable)
+// CHECK-LABEL: define{{( protected)?}} void @defaultD(%swift.opaque* noalias nocapture, %swift.type* %Self, i8** %SelfWitnessTable)
 // CHECK-NEXT:  entry:
 
 sil @defaultD : $@convention(witness_method) <Self where Self : ResilientProtocol> (@in_guaranteed Self) -> () {

test/IRGen/witness_method.sil

@@ -60,7 +60,7 @@ struct SyncUp<Deliverable> : Synergy {
   }
 }
 
-// CHECK-LABEL: define void @testGenericWitnessMethod(%swift.opaque* noalias nocapture sret, %V14witness_method6SyncUp* noalias nocapture, %swift.type* %T)
+// CHECK-LABEL: define{{( protected)?}} void @testGenericWitnessMethod(%swift.opaque* noalias nocapture sret, %V14witness_method6SyncUp* noalias nocapture, %swift.type* %T)
 // CHECK: entry:
 // CHECK:   [[METADATA:%.*]] = call %swift.type* @_TMaV14witness_method6SyncUp(%swift.type* %T)
 // CHECK:   [[WTABLE:%.*]] = call i8** @_TWaurGV14witness_method6SyncUpx_S_7SynergyS_(%swift.type* [[METADATA]])
@@ -86,7 +86,7 @@ protocol Strategy {
   func disrupt() -> GrowthHack
 }
 
-// CHECK-LABEL: define void @testArchetypeWitnessMethod(%swift.opaque* noalias nocapture sret, %swift.opaque* noalias nocapture, %swift.type* %T, i8** %T.Strategy, %swift.type* %T.GrowthHack, i8** %T.GrowthHack.Pivot)
+// CHECK-LABEL: define{{( protected)?}} void @testArchetypeWitnessMethod(%swift.opaque* noalias nocapture sret, %swift.opaque* noalias nocapture, %swift.type* %T, i8** %T.Strategy, %swift.type* %T.GrowthHack, i8** %T.GrowthHack.Pivot)
 // CHECK: entry:
 // CHECK:   [[WITNESS_ADDR:%.*]] = getelementptr inbounds i8*, i8** %T.Strategy, i32 2
 // CHECK:   [[WITNESS_FN:%.*]] = load i8*, i8** [[WITNESS_ADDR]]