Add support for JNI Library on Linux on PowerPC.

Summary:
Closes https://github.com/facebook/rocksdb/issues/1317
Closes https://github.com/facebook/rocksdb/pull/1845

Differential Revision: D4546491

Pulled By: siying

fbshipit-source-id: 86190b4

java/src/main/java/org/rocksdb/util/Environment.java

@@ -4,6 +4,10 @@ public class Environment {
   private static String OS = System.getProperty("os.name").toLowerCase();
   private static String ARCH = System.getProperty("os.arch").toLowerCase();
 
+  public static boolean isPowerPC() {
+    return ARCH.contains("ppc");
+  }
+
   public static boolean isWindows() {
     return (OS.contains("win"));
   }
@@ -36,16 +40,22 @@ public class Environment {
 
   public static String getJniLibraryName(final String name) {
     if (isUnix()) {
-      final String arch = (is64Bit()) ? "64" : "32";
-      return String.format("%sjni-linux%s", name, arch);
+      final String arch = is64Bit() ? "64" : "32";
+      if(isPowerPC()) {
+        return String.format("%sjni-linux-ppc%s", name, arch);
+      } else {
+        return String.format("%sjni-linux%s", name, arch);
+      }
     } else if (isMac()) {
       return String.format("%sjni-osx", name);
     } else if (isSolaris()) {
-      return String.format("%sjni-solaris%d", name, is64Bit() ? 64 : 32);
+      final String arch = is64Bit() ? "64" : "32";
+      return String.format("%sjni-solaris%s", name, arch);
     } else if (isWindows() && is64Bit()) {
       return String.format("%sjni-win64", name);
     }
-    throw new UnsupportedOperationException();
+
+    throw new UnsupportedOperationException(String.format("Cannot determine JNI library name for ARCH='%s' OS='%s' name='%s'", ARCH, OS, name));
   }
 
   public static String getJniLibraryFileName(final String name) {