- Fix building on OpenBSD/sparc64

Index: eval_defs.h
--- eval_defs.h.orig
+++ eval_defs.h
@@ -5,7 +5,7 @@
 #if defined(__sgi) || defined(__hpux)
 #include <alloca.h>
 #endif
-#ifdef sparc
+#if defined(__sparc) && defined(__sun) && defined(__SVR4)
 #include <malloc.h>
 #endif
 #include "fitsio2.h"
