[hackers] [scc] [cc1] Fix segfault in mktype() || Roberto E. Vargas Caballero

[git]

commit 4f5352fb2ecb3babe3122478bf0576f8905f1afc
Author:     Roberto E. Vargas Caballero <k...@shike2.com>
AuthorDate: Tue Feb 14 22:39:11 2017 +0100
Commit:     Roberto E. Vargas Caballero <k...@shike2.com>
CommitDate: Tue Feb 14 22:39:11 2017 +0100

    [cc1] Fix segfault in mktype()
    
    The patch 6ab66ac added a check about the last parameter
    in the parameter list, but this check was incorrect when nelem == 0,
    because we were accesing further or the borders of the array.

diff --git a/cc1/types.c b/cc1/types.c
index 7d446ef..a367d0b 100644
--- a/cc1/types.c
+++ b/cc1/types.c
@@ -301,7 +301,7 @@ mktype(Type *tp, int op, TINT nelem, Type *pars[])
                type.letter = L_FUNCTION;
                break;
        case FTN:
-               if (pars[nelem-1] == ellipsistype)
+               if (nelem > 0 && pars[nelem-1] == ellipsistype)
                        type.prop |= TELLIPSIS;
                type.letter = L_FUNCTION;
                break;