darwin, testsuite, ppc FIX PR87600

The test fails on PPC Darwin because we emit 
__POWERPC__ instead of __powerpc__ fixed by allowing
for both.

2019-05-15  Iain Sandoe  <iain@sandoe.co.uk>

	* gcc.dg/pr87600.h: Add __POWERPC__ as an alternate test
	for PowerPC platforms.

From-SVN: r271200

gcc/testsuite/gcc.dg/pr87600.h

@@ -7,7 +7,7 @@
 #elif defined (__i386__)
 # define REG1 "%eax"
 # define REG2 "%edx"
-#elif defined (__powerpc__)
+#elif defined (__powerpc__) || defined (__POWERPC__)
 # define REG1 "r3"
 # define REG2 "r4"
 #elif defined (__s390__)