Colin's const-fixing Patch Of Death. Seems to build fine on Windows

as well as Unix, so it can go in.

[originally from svn r3162]

unix/gtkdlg.c

@@ -2720,7 +2720,7 @@ void *eventlogstuff_new(void)
     return es;
 }
 
-void logevent_dlg(void *estuff, char *string)
+void logevent_dlg(void *estuff, const char *string)
 {
     struct eventlog_stuff *es = (struct eventlog_stuff *)estuff;
 

unix/pterm.c

@@ -166,7 +166,7 @@ int from_backend(void *frontend, int is_stderr, const char *data, int len)
     return term_data(inst->term, is_stderr, data, len);
 }
 
-void logevent(void *frontend, char *string)
+void logevent(void *frontend, const char *string)
 {
     struct gui_data *inst = (struct gui_data *)frontend;
 
@@ -3075,7 +3075,8 @@ int pt_main(int argc, char **argv)
 
     inst->back = select_backend(&inst->cfg);
     {
-	char *realhost, *error;
+	char *realhost;
+	const char *error;
 
 	error = inst->back->init((void *)inst, &inst->backhandle,
                                  &inst->cfg, inst->cfg.host, inst->cfg.port,

unix/pty.c

@@ -485,8 +485,8 @@ static void pty_uxsel_setup(void)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static char *pty_init(void *frontend, void **backend_handle, Config *cfg,
-		      char *host, int port, char **realhost, int nodelay)
+static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
+			    char *host, int port, char **realhost, int nodelay)
 {
     int slavefd;
     pid_t pid, pgrp;

unix/unix.h

@@ -64,7 +64,7 @@ void fatal_message_box(void *window, char *msg);
 void about_box(void *window);
 void *eventlogstuff_new(void);
 void showeventlog(void *estuff, void *parentwin);
-void logevent_dlg(void *estuff, char *string);
+void logevent_dlg(void *estuff, const char *string);
 int reallyclose(void *frontend);
 
 /* Things pterm.c needs from {ptermm,uxputty}.c */

unix/uxcons.c

@@ -258,7 +258,7 @@ void old_keyfile_warning(void)
     fputs(message, stderr);
 }
 
-void logevent(void *frontend, char *string)
+void logevent(void *frontend, const char *string)
 {
     log_eventlog(logctx, string);
 }

unix/uxnet.c

@@ -26,7 +26,7 @@
 struct Socket_tag {
     struct socket_function_table *fn;
     /* the above variable absolutely *must* be the first in this structure */
-    char *error;
+    const char *error;
     int s;
     Plug plug;
     void *private_ptr;
@@ -56,7 +56,7 @@ struct Socket_tag {
 typedef struct Socket_tag *Actual_Socket;
 
 struct SockAddr_tag {
-    char *error;
+    const char *error;
     /*
      * Which address family this address belongs to. AF_INET for
      * IPv4; AF_INET6 for IPv6; AF_UNSPEC indicates that name
@@ -115,7 +115,7 @@ void sk_cleanup(void)
     }
 }
 
-char *error_string(int error)
+const char *error_string(int error)
 {
     return strerror(error);
 }
@@ -322,7 +322,7 @@ static int sk_tcp_write_oob(Socket s, const char *data, int len);
 static void sk_tcp_set_private_ptr(Socket s, void *ptr);
 static void *sk_tcp_get_private_ptr(Socket s);
 static void sk_tcp_set_frozen(Socket s, int is_frozen);
-static char *sk_tcp_socket_error(Socket s);
+static const char *sk_tcp_socket_error(Socket s);
 
 static struct socket_function_table tcp_fn_table = {
     sk_tcp_plug,
@@ -837,8 +837,8 @@ static int net_select_result(int fd, int event)
 	    ret = recv(s->s, buf, sizeof(buf), MSG_OOB);
 	    noise_ultralight(ret);
 	    if (ret <= 0) {
-		char *str = (ret == 0 ? "Internal networking trouble" :
-			     error_string(errno));
+		const char *str = (ret == 0 ? "Internal networking trouble" :
+				   error_string(errno));
 		/* We're inside the Unix frontend here, so we know
 		 * that the frontend handle is unnecessary. */
 		logevent(NULL, str);
@@ -1003,11 +1003,11 @@ static void *sk_tcp_get_private_ptr(Socket sock)
  * if there's a problem. These functions extract an error message,
  * or return NULL if there's no problem.
  */
-char *sk_addr_error(SockAddr addr)
+const char *sk_addr_error(SockAddr addr)
 {
     return addr->error;
 }
-static char *sk_tcp_socket_error(Socket sock)
+static const char *sk_tcp_socket_error(Socket sock)
 {
     Actual_Socket s = (Actual_Socket) sock;
     return s->error;

unix/uxplink.c

@@ -574,7 +574,7 @@ int main(int argc, char **argv)
      */
     logctx = log_init(NULL, &cfg);
     {
-	char *error;
+	const char *error;
 	char *realhost;
 	/* nodelay is only useful if stdin is a terminal device */
 	int nodelay = cfg.tcp_nodelay && isatty(0);