Fix bogus builtin-snprintf-warn-3.c failure for avr

The test declares a struct with an array member that has INT_MAX/32767
elements. This causes a "type xxx is too large" error for targets like
the avr, which has 16 bit pointers.

Fix by marking the test as unsupported for targets with ptr size < 32.

2017-05-23  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>

	* gcc.dg/tree-ssa/builtin-snprintf-warn-3.c: Require ptr32plus.

From-SVN: r248361

gcc/testsuite/ChangeLog

+2017-05-23  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>
+
+	* gcc.dg/tree-ssa/builtin-snprintf-warn-3.c: Require ptr32plus.
+
 2017-05-22  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	PR target/80718

gcc/testsuite/gcc.dg/tree-ssa/builtin-snprintf-warn-3.c

 /* PR middle-end/79448 - unhelpful -Wformat-truncation=2 warning
    { dg-do compile }
-   { dg-options "-O2 -Wformat -Wformat-truncation=2 -ftrack-macro-expansion=0" } */
+   { dg-options "-O2 -Wformat -Wformat-truncation=2 -ftrack-macro-expansion=0" } 
+   { dg-require-effective-target ptr32plus } */
 
 typedef __SIZE_TYPE__  size_t;
 typedef __WCHAR_TYPE__ wchar_t;