diff --git a/c/bitvector.h b/c/bitvector.h
index d220ddd..f711d00 100644
--- a/c/bitvector.h
+++ b/c/bitvector.h
@@ -1,6 +1,3 @@
-#ifndef __BITVECTOR_H_
-#define __BITVECTOR_H_
-
 // a mask with n set lo or hi bits
 #define lomask(n) (u_int32_t)((((u_int32_t)1) << (n)) - 1)
 #define himask(n) (~lomask(32 - n))
@@ -67,5 +64,3 @@ void bitvector_xor_to(u_int32_t *dest, u_int32_t doffs, u_int32_t *a,
 u_int64_t bitvector_count(u_int32_t *b, u_int32_t offs, u_int64_t nbits);
 u_int32_t bitvector_any0(u_int32_t *b, u_int32_t offs, u_int32_t nbits);
 u_int32_t bitvector_any1(u_int32_t *b, u_int32_t offs, u_int32_t nbits);
-
-#endif
diff --git a/c/dirpath.h b/c/dirpath.h
index 5eddf50..b4e8444 100644
--- a/c/dirpath.h
+++ b/c/dirpath.h
@@ -1,6 +1,3 @@
-#ifndef __DIRPATH_H_
-#define __DIRPATH_H_
-
 #ifdef WIN32
 #define PATHSEP '\\'
 #define PATHSEPSTRING "\\"
@@ -20,5 +17,3 @@ void get_cwd(char *buf, size_t size);
 int set_cwd(char *buf);
 char *get_exename(char *buf, size_t size);
 void path_to_dirname(char *path);
-
-#endif
diff --git a/c/dtypes.h b/c/dtypes.h
index 45d1ff5..f8e4c65 100644
--- a/c/dtypes.h
+++ b/c/dtypes.h
@@ -1,6 +1,3 @@
-#ifndef __DTYPES_H_
-#define __DTYPES_H_
-
 /*
   This file defines sane integer types for our target platforms. This
   library only runs on machines with the following characteristics:
@@ -211,5 +208,3 @@ extern float F_PNAN;
 extern float F_NNAN;
 extern float F_PINF;
 extern float F_NINF;
-
-#endif
diff --git a/c/flisp.c b/c/flisp.c
index caf1c4b..149436d 100644
--- a/c/flisp.c
+++ b/c/flisp.c
@@ -59,8 +59,6 @@
 #include "random.h"
 #include "llt.h"
 
-#include "utils.h"
-
 #include "ieee754.h"
 
 #include "flisp.h"
@@ -415,8 +413,6 @@ value_t alloc_vector(size_t n, int init)
 // cvalues
 // --------------------------------------------------------------------
 
-#include "htable.h"
-#include "htableh_inc.h"
 #include "ptrhash.h"
 #include "operators.h"
 #include "cvalues.h"
diff --git a/c/flisp.h b/c/flisp.h
index a7acec6..1f3e374 100644
--- a/c/flisp.h
+++ b/c/flisp.h
@@ -1,6 +1,3 @@
-#ifndef FLISP_H
-#define FLISP_H
-
 typedef uptrint_t value_t;
 typedef int_t fixnum_t;
 typedef uint_t ufixnum_t;
@@ -417,5 +414,3 @@ value_t cvalue_wchar(value_t *args, uint32_t nargs);
 
 void fl_init(size_t initial_heapsize);
 int fl_load_system_image(value_t ios);
-
-#endif
diff --git a/c/hashing.h b/c/hashing.h
index 9891ba9..6764641 100644
--- a/c/hashing.h
+++ b/c/hashing.h
@@ -1,6 +1,3 @@
-#ifndef __HASHING_H_
-#define __HASHING_H_
-
 uint_t nextipow2(uint_t i);
 u_int32_t int32hash(u_int32_t a);
 u_int64_t int64hash(u_int64_t key);
@@ -12,5 +9,3 @@ u_int32_t int64to32hash(u_int64_t key);
 #endif
 u_int64_t memhash(const char *buf, size_t n);
 u_int32_t memhash32(const char *buf, size_t n);
-
-#endif
diff --git a/c/htable.h b/c/htable.h
index 7bd2b1a..a983d25 100644
--- a/c/htable.h
+++ b/c/htable.h
@@ -1,6 +1,3 @@
-#ifndef __HTABLE_H_
-#define __HTABLE_H_
-
 #define HT_N_INLINE 32
 
 struct htable {
@@ -18,5 +15,3 @@ void htable_free(struct htable *h);
 
 // clear and (possibly) change size
 void htable_reset(struct htable *h, size_t sz);
-
-#endif
diff --git a/c/ieee754.h b/c/ieee754.h
index de5a013..2d9be50 100644
--- a/c/ieee754.h
+++ b/c/ieee754.h
@@ -1,6 +1,3 @@
-#ifndef __IEEE754_H_
-#define __IEEE754_H_
-
 union ieee754_float {
     float f;
 
@@ -63,5 +60,3 @@ union ieee854_long_double {
 };
 
 #define IEEE854_LONG_DOUBLE_BIAS 0x3fff
-
-#endif
diff --git a/c/ios.h b/c/ios.h
index c143a75..aec3033 100644
--- a/c/ios.h
+++ b/c/ios.h
@@ -1,6 +1,3 @@
-#ifndef __IOS_H_
-#define __IOS_H_
-
 // this flag controls when data actually moves out to the underlying I/O
 // channel. memory streams are a special case of this where the data
 // never moves out.
@@ -204,5 +201,3 @@ int ios_ungetc(int c, struct ios *s);
   as optimizations, we do no writing if the buffer isn't "dirty", and we
   do no reading if the data will only be overwritten.
 */
-
-#endif
diff --git a/c/llt.h b/c/llt.h
index 1060970..5bd03bb 100644
--- a/c/llt.h
+++ b/c/llt.h
@@ -1,6 +1 @@
-#ifndef __LLT_H_
-#define __LLT_H_
-
 void llt_init();
-
-#endif
diff --git a/c/ptrhash.h b/c/ptrhash.h
index 890aa81..ebb4b1f 100644
--- a/c/ptrhash.h
+++ b/c/ptrhash.h
@@ -1,6 +1 @@
-#ifndef __PTRHASH_H_
-#define __PTRHASH_H_
-
 HTPROT(ptrhash)
-
-#endif
diff --git a/c/random.h b/c/random.h
index 0ea58e4..da1bffb 100644
--- a/c/random.h
+++ b/c/random.h
@@ -1,6 +1,3 @@
-#ifndef __LLTRANDOM_H_
-#define __LLTRANDOM_H_
-
 #define random() genrand_int32()
 #define srandom(n) init_genrand(n)
 double rand_double();
@@ -10,5 +7,3 @@ void randomize();
 uint32_t genrand_int32();
 void init_genrand(uint32_t s);
 u_int64_t i64time();
-
-#endif
diff --git a/c/socket.h b/c/socket.h
index 559b6be..2f3d663 100644
--- a/c/socket.h
+++ b/c/socket.h
@@ -1,6 +1,3 @@
-#ifndef __LLTSOCKET_H_
-#define __LLTSOCKET_H_
-
 #ifdef WIN32
 #include <winsock2.h>
 #else
@@ -27,5 +24,3 @@ void bzero(void *s, size_t n);
 #ifndef WIN32
 void closesocket(int fd);
 #endif
-
-#endif
diff --git a/c/timefuncs.h b/c/timefuncs.h
index b222572..a166063 100644
--- a/c/timefuncs.h
+++ b/c/timefuncs.h
@@ -1,11 +1,6 @@
-#ifndef __TIMEFUNCS_H_
-#define __TIMEFUNCS_H_
-
 u_int64_t i64time();
 double clock_now();
 void timestring(double seconds, char *buffer, size_t len);
 double parsetime(const char *str);
 void sleep_ms(int ms);
 void timeparts(int32_t *buf, double t);
-
-#endif
diff --git a/c/utf8.h b/c/utf8.h
index 0c3d231..3f8314a 100644
--- a/c/utf8.h
+++ b/c/utf8.h
@@ -1,19 +1,3 @@
-#ifndef __UTF8_H_
-#define __UTF8_H_
-
-#if !defined(MACOSX)
-#if !defined(__DTYPES_H_) && !defined(_SYS_TYPES_H)
-typedef char int8_t;
-typedef short int16_t;
-typedef int int32_t;
-typedef long long int64_t;
-typedef unsigned char u_int8_t;
-typedef unsigned short u_int16_t;
-typedef unsigned int u_int32_t;
-typedef unsigned long long u_int64_t;
-#endif
-#endif
-
 extern int locale_is_utf8;
 
 #if defined(__WIN32__)
@@ -128,5 +112,3 @@ int u8_isvalid(const char *str, int length);
 /* reverse a UTF-8 string. len is length in bytes. dest and src must both
    be allocated to at least len+1 bytes. returns 1 for error, 0 otherwise */
 int u8_reverse(char *dest, char *src, size_t len);
-
-#endif
diff --git a/c/utils.h b/c/utils.h
index 57e9c72..42e42ba 100644
--- a/c/utils.h
+++ b/c/utils.h
@@ -1,6 +1,3 @@
-#ifndef __UTILS_H_
-#define __UTILS_H_
-
 #if defined(__amd64__) || defined(_M_AMD64)
 #define ARCH_X86_64
 #define __CPU__ 686
@@ -108,5 +105,3 @@ STATIC_INLINE u_int64_t ByteSwap64(u_int64_t x)
 #define bswap_64(x) ByteSwap64(x)
 
 #endif
-
-#endif