vwebp: msvc build tweaks

snprintf -> _snprintf / remove double->float warnings

Change-Id: I5dcdc394cf7e2d37205beaf83ed0f80a18ec06ab
diff --git a/examples/vwebp.c b/examples/vwebp.c
index 4e98220..553a603 100644
--- a/examples/vwebp.c
+++ b/examples/vwebp.c
@@ -30,6 +30,10 @@
 #endif
 #endif
 
+#ifdef _MSC_VER
+#define snprintf _snprintf
+#endif
+
 // Unfortunate global variables
 static const WebPDecBuffer* kPic = NULL;
 static const char* file_name = NULL;
@@ -87,12 +91,12 @@
     char tmp[32];
 
     glColor4f(0.0, 0.0, 0.0, 0.0);
-    glRasterPos2f(-0.95, 0.90);
+    glRasterPos2f(-0.95f, 0.90f);
     PrintString(file_name);
 
     snprintf(tmp, sizeof(tmp), "Dimension:%d x %d", kPic->width, kPic->height);
     glColor4f(0.0, 0.0, 0.0, 0.0);
-    glRasterPos2f(-0.95, 0.80);
+    glRasterPos2f(-0.95f, 0.80f);
     PrintString(tmp);
   }
   glFlush();