In cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c, the

dt_popc() function assumes that either _ILP32 or _LP64 is defined,
otherwise it has no suitable implementation.

However, the _ILP32 and _LP64 macros come from isa_defs.h, which is not
included in this file.  Add the include now, to get the macros defined.

MFC after:	1 week

cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c

@@ -27,6 +27,7 @@
 #if defined(sun)
 #include <sys/sysmacros.h>
 #endif
+#include <sys/isa_defs.h>
 
 #include <strings.h>
 #include <unistd.h>