bit more of a robust method of checking if running on a 32-bit jvm

os.arch can have a wide variety of values (e.g. not just "x86" for
32 bit)

manual-bwapi-src/Mirror.java

@@ -76,11 +76,17 @@ public class Mirror {
         return true;
     }
 
+    public static boolean is64BitJRE() {
+        String bits = System.getProperty("sun.arch.data.model");
+        if (bits == null)
+            return System.getProperty("java.vm.name").contains("64");
+        else
+            return bits.equals("64");
+    }
+
     static {
-        String arch = System.getProperty("os.arch");
+        if (is64BitJRE())
-        if(!arch.equals("x86")){
+            throw new UnsupportedOperationException("BWMirror must be run on a 32-bit JRE/JDK.");
-            throw new UnsupportedOperationException("BWMirror API supports only x86 architecture.");
-        }
 
         if (!extractAndLoadNativeLibraries())
             System.exit(1);