Fix bogus pr78886.c failure for avr

The test fails for avr because malloc has been declared to take
an unsigned long, whereas size_t for avr is only unsigned int.

Fixed by typedef'ing __SIZE_TYPE__ to size_t and using it in the
malloc function declaration.

gcc/testsuite/

2017-05-17  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>

	* gcc.dg/tree-ssa/pr78886.c: Use __SIZE_TYPE__ instead of
	unsigned long.

From-SVN: r248138

gcc/testsuite/ChangeLog

+2017-05-17  Senthil Kumar Selvaraj  <senthil_kumar.selvaraj@atmel.com>
+
+	* gcc.dg/tree-ssa/pr78886.c: Use __SIZE_TYPE__ instead of
+	unsigned long.
+
 2017-05-17  Chenghua Xu  <paul.hua.gm@gmail.com>
 
 	* gcc.target/mips/reorgbug-1.c: Don't specify -O2.

gcc/testsuite/gcc.dg/tree-ssa/pr78886.c

 /* { dg-do compile } */
 /* { dg-options "-O2" } */
-void *malloc(unsigned long x);
+
+__extension__ typedef __SIZE_TYPE__ size_t;
+void *malloc(size_t x);
 
 void foo(void)
 {