Convert // comment marks to /**/ in order to fix FTBS on ia64

https://bugs.gentoo.org/show_bug.cgi?id=447740

Patch written by Kacper Kowalik <xarthisius@gentoo.org>
--- a/test/th5s.c
+++ b/test/th5s.c
@@ -730,8 +730,8 @@ test_h5s_zero_dim(void)
         ret = H5Pset_chunk(plist_id, SPACE1_RANK, chunk_dims);
         CHECK(ret, FAIL, "H5Pset_chunk");
 
-        // ret = H5Pset_alloc_time(plist_id, alloc_time);
-        // CHECK(ret, FAIL, "H5Pset_alloc_time");
+        /* ret = H5Pset_alloc_time(plist_id, alloc_time);
+           CHECK(ret, FAIL, "H5Pset_alloc_time"); */
 
         dset1 = H5Dcreate2(fid1, BASICDATASET1, H5T_NATIVE_INT, sid_chunk, H5P_DEFAULT, plist_id, H5P_DEFAULT);
         CHECK(dset1, FAIL, "H5Dcreate2");
--- a/tools/h5dump/h5dump_ddl.c
+++ b/tools/h5dump/h5dump_ddl.c
@@ -1341,8 +1341,8 @@ handle_attributes(hid_t fid, const char *attr, void UNUSED * data, int UNUSED pe
     string_dataformat.do_escape = display_escape;
     outputformat = &string_dataformat;
 
-    //attr_name = attr + j + 1;
-	// need to replace escape characters
+    /* attr_name = attr + j + 1; */
+	/* need to replace escape characters */
 	attr_name = h5tools_str_replace(attr + j + 1, "\\/", "/");
 
 
--- a/tools/lib/h5tools_str.c
+++ b/tools/lib/h5tools_str.c
@@ -632,7 +632,7 @@ h5tools_str_indent(h5tools_str_t *str, const h5tool_format_t *info,
         h5tools_str_append(str, "%s", OPT(info->line_indent, ""));
     }
 
-//    ctx->need_prefix = 0;
+      /* ctx->need_prefix = 0; */
 }
 
 /*-------------------------------------------------------------------------