[java-atk-wrapper] fix compiling warning

[Samuel Thibault <sthibaul src gnome org>]

commit eeabf606381dd1bff4ceab04e39bca29bdcb7e57
Author: giuseppe <giuseppe dhcp-64-92 muc redhat com>
Date:   Fri Jul 5 12:23:27 2019 +0200

    fix compiling warning

 jni/src/AtkWrapper.c | 4 ++--
 jni/src/jawimpl.c    | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/jni/src/AtkWrapper.c b/jni/src/AtkWrapper.c
index 194f95c..907e6e2 100644
--- a/jni/src/AtkWrapper.c
+++ b/jni/src/AtkWrapper.c
@@ -1193,9 +1193,9 @@ JNICALL Java_org_GNOME_Accessibility_AtkWrapper_getInstance(JNIEnv *jniEnv,
                                                             jobject ac)
 {
   if (!ac)
-    return NULL;
+    return 0;
 
-  return jaw_impl_get_instance(jniEnv, ac);
+  return (jlong) jaw_impl_get_instance(jniEnv, ac);
 }
 
 #ifdef __cplusplus
diff --git a/jni/src/jawimpl.c b/jni/src/jawimpl.c
index 21391d4..df7e50f 100644
--- a/jni/src/jawimpl.c
+++ b/jni/src/jawimpl.c
@@ -312,7 +312,7 @@ jaw_impl_get_instance_from_jaw (JNIEnv *jniEnv, jobject ac)
   jclass classWrapper = (*jniEnv)->FindClass(jniEnv, "org/GNOME/Accessibility/AtkWrapper");
   jmethodID jmid = (*jniEnv)->GetStaticMethodID(jniEnv, classWrapper, "getInstanceFromSwing", 
"(Ljavax/accessibility/AccessibleContext;)J");
   jlong ptr = (*jniEnv)->CallStaticLongMethod(jniEnv, classWrapper, jmid, ac);
-  return ptr;
+  return (JawImpl*) ptr;
 }
 
 JawImpl*