[libclang] Add some constness in CXSourceLocation and CXSourceRange.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172261 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index 0214a7d..6fa8296 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -342,7 +342,7 @@
  * to map a source location to a particular file, line, and column.
  */
 typedef struct {
-  void *ptr_data[2];
+  const void *ptr_data[2];
   unsigned int_data;
 } CXSourceLocation;
 
@@ -353,7 +353,7 @@
  * starting and end locations from a source range, respectively.
  */
 typedef struct {
-  void *ptr_data[2];
+  const void *ptr_data[2];
   unsigned begin_int_data;
   unsigned end_int_data;
 } CXSourceRange;