remove ZLIB include from SkUserConfig for how (doesn't work on mac sampleapp) but,
add it to Makefile if SKIA_PDF_SUPPORT is true

Use compile_assert (yea!)



git-svn-id: http://skia.googlecode.com/svn/trunk@643 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/config/SkUserConfig.h b/include/config/SkUserConfig.h
index 721f5f7..a2df745 100644
--- a/include/config/SkUserConfig.h
+++ b/include/config/SkUserConfig.h
@@ -121,7 +121,7 @@
     algorithm (used in PDF generation), define SK_ZLIB_INCLUDE to be the
     include path.
  */
-#define SK_ZLIB_INCLUDE <zlib.h>
+//#define SK_ZLIB_INCLUDE <zlib.h>
 
 /*  If SK_DEBUG is defined, then you can optionally define SK_SUPPORT_UNITTEST
     which will run additional self-tests at startup. These can take a long time,