diff --git a/c/cvalues.h b/c/cvalues.h
index 49efc37..612010e 100644
--- a/c/cvalues.h
+++ b/c/cvalues.h
@@ -1293,7 +1293,7 @@ static int num_to_ptr(value_t a, fixnum_t *pi, numerictype_t *pt, void **pp)
 */
 int numeric_compare(value_t a, value_t b, int eq, int eqnans, char *fname)
 {
-    int_t ai, bi;
+    intptr_t ai, bi;
     numerictype_t ta, tb;
     void *aptr, *bptr;
 
@@ -1336,7 +1336,7 @@ static void DivideByZeroError(void)
 static value_t fl_div2(value_t a, value_t b)
 {
     double da, db;
-    int_t ai, bi;
+    intptr_t ai, bi;
     numerictype_t ta, tb;
     void *aptr, *bptr;
 
@@ -1360,7 +1360,7 @@ static value_t fl_div2(value_t a, value_t b)
 
 static value_t fl_idiv2(value_t a, value_t b)
 {
-    int_t ai, bi;
+    intptr_t ai, bi;
     numerictype_t ta, tb;
     void *aptr, *bptr;
     int64_t a64, b64;
@@ -1407,7 +1407,7 @@ div_error:
 
 static value_t fl_bitwise_op(value_t a, value_t b, int opcode, char *fname)
 {
-    int_t ai, bi;
+    intptr_t ai, bi;
     numerictype_t ta, tb, itmp;
     void *aptr = NULL, *bptr = NULL, *ptmp;
     int64_t b64;
diff --git a/c/dtypes.h b/c/dtypes.h
index 0835f18..c04fd20 100644
--- a/c/dtypes.h
+++ b/c/dtypes.h
@@ -104,8 +104,6 @@ typedef int bool_t;
 #ifdef BITS64
 #define TOP_BIT 0x8000000000000000
 #define NBITS 64
-typedef unsigned long uint_t;  // preferred int type on platform
-typedef long int_t;
 typedef int64_t offset_t;
 typedef uint64_t index_t;
 typedef int64_t ptrint_t;  // pointer-size int
@@ -113,8 +111,6 @@ typedef uint64_t u_ptrint_t;
 #else
 #define TOP_BIT 0x80000000
 #define NBITS 32
-typedef unsigned long uint_t;
-typedef long int_t;
 typedef int32_t offset_t;
 typedef uint32_t index_t;
 typedef int32_t ptrint_t;
diff --git a/c/flisp.h b/c/flisp.h
index 8b418dd..8aca541 100644
--- a/c/flisp.h
+++ b/c/flisp.h
@@ -1,6 +1,6 @@
 typedef uptrint_t value_t;
-typedef int_t fixnum_t;
-typedef uint_t ufixnum_t;
+typedef intptr_t fixnum_t;
+typedef uintptr_t ufixnum_t;
 #ifdef BITS64
 #define T_FIXNUM T_INT64
 #else
diff --git a/c/hashing.c b/c/hashing.c
index 42a1ba1..0511256 100644
--- a/c/hashing.c
+++ b/c/hashing.c
@@ -27,7 +27,7 @@ typedef unsigned short uint16_t;
 #include "ios.h"
 #include "random.h"
 
-uint_t nextipow2(uint_t i)
+uintptr_t nextipow2(uintptr_t i)
 {
     if (i == 0)
         return 1;
diff --git a/c/hashing.h b/c/hashing.h
index ced1e07..b974e78 100644
--- a/c/hashing.h
+++ b/c/hashing.h
@@ -1,4 +1,4 @@
-uint_t nextipow2(uint_t i);
+uintptr_t nextipow2(uintptr_t i);
 uint32_t int32hash(uint32_t a);
 uint64_t int64hash(uint64_t key);
 uint32_t int64to32hash(uint64_t key);
diff --git a/c/htable_inc.h b/c/htable_inc.h
index 0e902ca..5b27bcb 100644
--- a/c/htable_inc.h
+++ b/c/htable_inc.h
@@ -13,7 +13,7 @@
 #define HTIMPL(HTNAME, HFUNC, EQFUNC)                                        \
     static void **HTNAME##_lookup_bp(struct htable *h, void *key)            \
     {                                                                        \
-        uint_t hv;                                                           \
+        uintptr_t hv;                                                        \
         size_t i, orig, index, iter;                                         \
         size_t newsz, sz = hash_size(h);                                     \
         size_t maxprobe = max_probe(sz);                                     \