sh: Check readonly status for assignments on regular builtins.

An error message is written, the builtin is not executed, nonzero exit
status is returned but the shell does not abort.

This was already checked for special builtins and external commands, with
the same consequences except that the shell aborts for special builtins.

Obtained from:	NetBSD

1 files changed, 2 insertions, 1 deletions

diff --git a/bin/sh/var.h b/bin/sh/var.h
index 1ec707b..775db41 100644
--- a/bin/sh/var.h
+++ b/bin/sh/var.h
@@ -45,6 +45,7 @@
 #define VSTACK		0x10	/* text is allocated on the stack */
 #define VUNSET		0x20	/* the variable is not set */
 #define VNOFUNC		0x40	/* don't call the callback function */
+#define VNOSET		0x80	/* do not set variable - just readonly test */
 
 
 struct var {
@@ -106,7 +107,7 @@ void initvar(void);
 void setvar(const char *, const char *, int);
 void setvareq(char *, int);
 struct strlist;
-void listsetvar(struct strlist *);
+void listsetvar(struct strlist *, int);
 char *lookupvar(const char *);
 char *bltinlookup(const char *, int);
 void bltinsetlocale(void);