[K/N] Update libffi for Windows

MinGW and MSVC are hardly compatible in case of static linkage, so we
need to use a native libffi.

kotlin-native/Interop/Runtime/build.gradle.kts

@@ -32,6 +32,7 @@ plugins {
 native {
     val isWindows = PlatformInfo.isWindows()
     val obj = if (isWindows) "obj" else "o"
+    val lib = if (isWindows) "lib" else "a"
     val host = rootProject.project(":kotlin-native").extra["hostName"]
     val hostLibffiDir = rootProject.project(":kotlin-native").extra["${host}LibffiDir"]
     val cflags = mutableListOf("-I$hostLibffiDir/include",
@@ -54,7 +55,7 @@ native {
         flags("-shared",
               "-o",ruleOut(), *ruleInAll(),
               "-L${project(":kotlin-native:libclangext").buildDir}",
-              "$hostLibffiDir/lib/libffi.a",
+              "$hostLibffiDir/lib/libffi.$lib",
               "-lclangext")
     }
     tasks.named(solib("callbacks")).configure {