Move __alpha to port/alpha.h.

src/include/port/alpha.h

@@ -3,3 +3,9 @@
 #define HAS_TEST_AND_SET
 #include <sys/mman.h>			/* for msemaphore */
 typedef msemaphore slock_t;
+
+/* some platforms define __alpha, but not __alpha__ */
+#if defined(__alpha) && !defined(__alpha__)
+#define __alpha__
+#endif
+

src/makefiles/Makefile.alpha

-/* some platforms define __alpha, but not __alpha__ */
-#if defined(__alpha) && !defined(__alpha__)
-#define __alpha__
-#endif
-
 %.so:  %.o
 	$(LD) -shared -expect_unresolved '*' -o $@ $<