diff --git a/src/mzscheme/src/gmp/gmp-mparam.h b/src/mzscheme/src/gmp/gmp-mparam.h
index e0fcf1c2f6..3fdb743e5a 100644
--- a/src/mzscheme/src/gmp/gmp-mparam.h
+++ b/src/mzscheme/src/gmp/gmp-mparam.h
@@ -19,6 +19,12 @@ along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 MA 02111-1307, USA. */
 
+#ifdef SIZEOF_LONG
+# if SIZEOF_LONG == 8
+#  define SIXTY_FOUR_BIT_INTEGERS
+# endif
+#endif
+
 #if defined(SIXTY_FOUR_BIT_INTEGERS) || defined(_LONG_LONG_LIMB)
 # define BITS_PER_MP_LIMB 64
 # define BYTES_PER_MP_LIMB 8
diff --git a/src/mzscheme/src/gmp/gmp.c b/src/mzscheme/src/gmp/gmp.c
index 14dfed07cb..82a32e16eb 100644
--- a/src/mzscheme/src/gmp/gmp.c
+++ b/src/mzscheme/src/gmp/gmp.c
@@ -30,6 +30,7 @@ extern void free(void *);
 #define FREE(p, s) free(p)
 
 #include "../../sconfig.h"
+#include "mzconfig.h"
 #include "gmp.h"
 #include "gmp-impl.h"
 #include "gmplonglong.h"
diff --git a/src/mzscheme/src/thread.c b/src/mzscheme/src/thread.c
index fa9a28d463..3339c60336 100644
--- a/src/mzscheme/src/thread.c
+++ b/src/mzscheme/src/thread.c
@@ -37,18 +37,6 @@
 # define SCHEME_NO_GC_PROTO
 #endif
 
-#if defined(mips) || defined(__mips)
-/* Irix SPROCS needs to load some files first, so find out if we're SPROCS. */
-# include "../sconfig.h"
-
-# ifdef MZ_USE_IRIX_SPROCS
-/* Don't include anything else before this */
-#  include "../gc/gc.h"
-#  include "../gc/semaphores.h"
-#  include "../gc/sproc.h"
-# endif
-#endif
-
 #include "schpriv.h"
 #include "schmach.h"
 #include "schgc.h"