commit f3b4beb18f256e733a4c699e96118d47a2191b74
Author: Shiro Kawai <shiro@acm.org>
Date:   Wed Dec 23 16:22:10 2020 -1000

    Fix sys-ctermid out-of-extent memory access bug

    https://github.com/shirok/Gauche/issues/740

diff --git a/src/libsys.scm b/src/libsys.scm
index f253c08a4..7f433c184 100644
--- a/src/libsys.scm
+++ b/src/libsys.scm
@@ -460,11 +460,11 @@
 (define-cproc sys-mkdtemp (template::<string>) Scm_SysMkdtemp)
 
 ;; ctermid
-(define-cproc sys-ctermid () ::<const-cstring>
+(define-cproc sys-ctermid ()
   (.if "defined(GAUCHE_WINDOWS)"
-       (return "CON")
+       (return '"CON")
        (let* ([buf::(.array char [(+ L_ctermid 1)])])
-         (return (ctermid buf)))))
+         (return (SCM_MAKE_STR_COPYING (ctermid buf))))))
 
 ;;---------------------------------------------------------------------
 ;; stdlib.h