mouse shortcuts: don't hardcode selpaste

Because selpaste is activated on release, a release flag was added to
mouse shortcuts which controls whether activation is on press/release,
and selpaste binding to button2 was moved to config.h .

button1 remains the only hardcoded mouse button - for selection + copy.

config.def.h

@@ -162,7 +162,8 @@ static uint forcemousemod = ShiftMask;
  * Beware that overloading Button1 will disable the selection.
  */
 static MouseShortcut mshortcuts[] = {
-	/* mask                 button   function        argument */
+	/* mask                 button   function        argument       release */
+	{ XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
 	{ XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
 	{ XK_ANY_MOD,           Button5, ttysend,        {.s = "\005"} },
 };

x.c

@@ -33,6 +33,7 @@ typedef struct {
 	uint button;
 	void (*func)(const Arg *);
 	const Arg arg;
+	uint  release;
 } MouseShortcut;
 
 typedef struct {
@@ -165,6 +166,7 @@ static void kpress(XEvent *);
 static void cmessage(XEvent *);
 static void resize(XEvent *);
 static void focus(XEvent *);
+static int mouseaction(XEvent *, uint);
 static void brelease(XEvent *);
 static void bpress(XEvent *);
 static void bmotion(XEvent *);
@@ -416,11 +418,27 @@ mousereport(XEvent *e)
 	ttywrite(buf, len, 0);
 }
 
+int
+mouseaction(XEvent *e, uint release)
+{
+	MouseShortcut *ms;
+
+	for (ms = mshortcuts; ms < mshortcuts + LEN(mshortcuts); ms++) {
+		if (ms->release == release &&
+		    ms->button == e->xbutton.button &&
+		    match(ms->mod, e->xbutton.state & ~forcemousemod)) {
+			ms->func(&(ms->arg));
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
 void
 bpress(XEvent *e)
 {
 	struct timespec now;
-	MouseShortcut *ms;
 	int snap;
 
 	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forcemousemod)) {
@@ -428,13 +446,8 @@ bpress(XEvent *e)
 		return;
 	}
 
-	for (ms = mshortcuts; ms < mshortcuts + LEN(mshortcuts); ms++) {
-		if (e->xbutton.button == ms->button &&
-		    match(ms->mod, e->xbutton.state & ~forcemousemod)) {
-			ms->func(&(ms->arg));
-			return;
-		}
-	}
+	if (mouseaction(e, 0))
+		return;
 
 	if (e->xbutton.button == Button1) {
 		/*
@@ -655,9 +668,9 @@ brelease(XEvent *e)
 		return;
 	}
 
-	if (e->xbutton.button == Button2)
-		selpaste(NULL);
-	else if (e->xbutton.button == Button1)
+	if (mouseaction(e, 1))
+		return;
+	if (e->xbutton.button == Button1)
 		mousesel(e, 1);
 }