devdraw: enable retina behavior by default on OS X

Change-Id: I243a1fe3f9ec0841570c4cd69c02be9cfd9ade50
Reviewed-on: https://plan9port-review.googlesource.com/1172
Reviewed-by: Russ Cox <rsc@swtch.com>

src/cmd/devdraw/cocoa-screen.m

diff --git a/src/cmd/devdraw/cocoa-screen.m b/src/cmd/devdraw/cocoa-screen.m
index 1e9ba3f..0335536 100644
--- a/src/cmd/devdraw/cocoa-screen.m
+++ b/src/cmd/devdraw/cocoa-screen.m
@@ -41,10 +41,10 @@
 static void setprocname(const char*);
 
 /*
- * By default, devdraw ignores retina displays. A non-zero evironment variable
- * |devdrawretina| will override this.
+ * By default, devdraw uses retina displays.
+ * Set devdrawretina=0 in the environment to override.
  */
-int devdrawretina = 0;
+int devdrawretina = 1;
 
 void
 usage(void)