[nasm:nasm-2.12.xx] preproc: Don't dereference nil @istk

[nasm-bot f. C. G. <gor...@gm...>]

Commit-ID:  771d04e263f16ed496da3573e8b0481d7c25314d
Gitweb:     http://repo.or.cz/w/nasm.git?a=commitdiff;h=771d04e263f16ed496da3573e8b0481d7c25314d
Author:     Cyrill Gorcunov <gor...@gm...>
AuthorDate: Tue, 10 May 2016 23:27:03 +0300
Committer:  Cyrill Gorcunov <gor...@gm...>
CommitDate: Tue, 10 May 2016 23:27:03 +0300

preproc: Don't dereference nil @istk

If not input was specified istk = NULL, so don't dereference it.

Signed-off-by: Cyrill Gorcunov <gor...@gm...>


---
 preproc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/preproc.c b/preproc.c
index 0c9bf2d..9dc3d88 100644
--- a/preproc.c
+++ b/preproc.c
@@ -5277,7 +5277,8 @@ static void pp_error_list_macros(int severity)
     severity |= ERR_PP_LISTMACRO | ERR_NO_SEVERITY;
     src_get(&saved_line, &saved_fname);
 
-    pp_list_one_macro(istk->mstk, severity);
+    if (istk)
+        pp_list_one_macro(istk->mstk, severity);
 
     src_set(saved_line, saved_fname);
 }