Ensure linker from sysroot is used (#834)

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt

@@ -518,7 +518,6 @@ internal class NativeIndexImpl(val library: NativeLibrary) : NativeIndex() {
                 clang_disposeTokens(translationUnit, tokens, numTokens)
             }
         }
-        TODO()
     }
 
     private fun isSuitableFunction(cursor: CValue<CXCursor>): Boolean {

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt

@@ -244,7 +244,8 @@ private fun Properties.defaultCompilerOpts(target: String, dependencies: String)
             val libGcc = getTargetSpecific("libGcc", target)
             val binDir = "$targetSysRoot/${libGcc ?: "bin"}"
             return archSelector + commonArgs + listOf(
-                    "-B$binDir", "--gcc-toolchain=$targetToolchain")
+                    "-B$binDir", "--gcc-toolchain=$targetToolchain",
+                    "-fuse-ld=$targetToolchain/bin/ld")
         }
         "mingw" -> {
             return archSelector + commonArgs + listOf("-B$targetSysRoot/bin")