vis: add #defines to ease overriding of utility names

This should ease packaging for systems with an existing vis(1) binary.

Author: martanne

register.c

@@ -6,6 +6,10 @@
 #include "util.h"
 #include "register.h"
 
+#ifndef VIS_CLIPBOARD
+#define VIS_CLIPBOARD "vis-clipboard"
+#endif
+
 static ssize_t read_buffer(void *context, char *data, size_t len) {
 	buffer_append(context, data, len);
 	return len;
@@ -30,7 +34,7 @@ const char *register_get(Vis *vis, Register *reg, size_t *len) {
 		buffer_clear(&reg->buf);
 
 		int status = vis_pipe(vis, &(Filerange){ .start = 0, .end = 0 },
-			(const char*[]){ "vis-clipboard", "--paste", NULL },
+			(const char*[]){ VIS_CLIPBOARD, "--paste", NULL },
 			&reg->buf, read_buffer, &buferr, read_buffer);
 
 		if (status != 0)
@@ -70,7 +74,7 @@ bool register_put_range(Vis *vis, Register *reg, Text *txt, Filerange *range) {
 		Buffer buferr;
 		buffer_init(&buferr);
 
-		int status = vis_pipe(vis, range, (const char*[]){ "vis-clipboard", "--copy", NULL },
+		int status = vis_pipe(vis, range, (const char*[]){ VIS_CLIPBOARD, "--copy", NULL },
 			NULL, NULL, &buferr, read_buffer);
 
 		if (status != 0)

vis-cmds.c

@@ -1,5 +1,9 @@
 /* this file is included from sam.c */
 
+#ifndef VIS_OPEN
+#define VIS_OPEN "vis-open"
+#endif
+
 static void windows_arrange(Vis *vis, enum UiLayout layout) {
 	vis->ui->arrange(vis->ui, layout);
 }
@@ -262,7 +266,7 @@ static const char *file_open_dialog(Vis *vis, const char *pattern) {
 	buffer_init(&bufout);
 	buffer_init(&buferr);
 
-	if (!buffer_put0(&bufcmd, "vis-open ") || !buffer_append0(&bufcmd, pattern ? pattern : ""))
+	if (!buffer_put0(&bufcmd, VIS_OPEN " ") || !buffer_append0(&bufcmd, pattern ? pattern : ""))
 		return NULL;
 
 	Filerange empty = text_range_empty();