fix: comment out main, so there is only one main signature.

dwm.c also has a main function defined.

src/transient.c

@@ -5,6 +5,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
+/*
 int main(void) {
 	Display *d;
 	Window r, f, t = None;
@@ -40,3 +41,4 @@ int main(void) {
 	XCloseDisplay(d);
 	exit(0);
 }
+*/