Remove unused Truffle::LIBC

Author: eregon

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -720,7 +720,6 @@ private void initializeConstants() {
         setConstant(objectClass, "ARGV", argv);
 
         setConstant(truffleModule, "UNDEFINED", supportUndefined);
-        setConstant(truffleModule, "LIBC", frozenUSASCIIString(Platform.LIBC));
 
         setConstant(encodingConverterClass, "INVALID_MASK", EConvFlags.INVALID_MASK);
         setConstant(encodingConverterClass, "INVALID_REPLACE", EConvFlags.INVALID_REPLACE);

src/main/java/org/truffleruby/platform/Platform.java

@@ -31,23 +31,10 @@
 
 public abstract class Platform extends BasicPlatform {
 
-    public static final String LIBPREFIX = OS == OS_TYPE.WINDOWS ? "" : "lib";
     public static final String LIBSUFFIX = determineLibExt();
-    public static final String LIBC = determineLibC();
 
     public static final boolean IS_WINDOWS = OS == OS_TYPE.WINDOWS;
 
-    private static final String determineLibC() {
-        switch (OS) {
-            case WINDOWS:
-                return "msvcrt.dll";
-            case LINUX:
-                return "libc.so.6";
-            default:
-                return LIBPREFIX + "c." + LIBSUFFIX;
-        }
-    }
-
     private static final String determineLibExt() {
         switch (OS) {
             case WINDOWS: