Fix ks_errno signature to return ks_err instead of uint

include/keystone/keystone.h

@@ -224,7 +224,7 @@ ks_err ks_close(ks_engine *ks);
  @return: error code of ks_err enum type (KS_ERR_*, see above)
 */
 KEYSTONE_EXPORT
-unsigned int ks_errno(ks_engine *ks);
+ks_err ks_errno(ks_engine *ks);
 
 
 /*

llvm/keystone/ks.cpp

@@ -33,9 +33,9 @@ unsigned int ks_version(unsigned int *major, unsigned int *minor)
 
 
 KEYSTONE_EXPORT
-unsigned int ks_errno(ks_engine *ks)
+ks_err ks_errno(ks_engine *ks)
 {
-    return ks->errnum;
+    return (ks_err)ks->errnum;
 }