diff --git a/configure.ac b/configure.ac
index fe19787..3161620 100644
--- a/configure.ac
+++ b/configure.ac
@@ -164,8 +164,8 @@ AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS([sys/ioctl.h sys/mman.h sys/resource.h \
 		  sys/select.h sys/socket.h sys/time.h sys/uio.h \
 		  sys/un.h arpa/inet.h netinet/in.h \
-		  assert.h ctype.h errno.h fcntl.h grp.h io.h libintl.h \
-		  netdb.h pwd.h regex.h signal.h stdarg.h stddef.h stdio.h \
+		  assert.h errno.h fcntl.h grp.h io.h libintl.h \
+		  netdb.h pwd.h regex.h signal.h stdarg.h \
 		  sysexits.h syslog.h time.h wchar.h wctype.h \
 		  values.h])
 
diff --git a/src/common.h b/src/common.h
index 89a054f..7f5ce9b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -32,6 +32,16 @@
 /*
  * Include standard headers which are used through-out tinyproxy
  */
+
+/* standard C headers - we can safely assume they exist. */
+#include	<stddef.h>
+#include	<stdint.h>
+#include	<ctype.h>
+#include	<stdio.h>
+#include	<stdlib.h>
+#include	<string.h>
+#include	<unistd.h>
+
 #ifdef HAVE_SYS_TYPES_H
 #  include      <sys/types.h>
 #endif
@@ -41,12 +51,6 @@
 #ifdef HAVE_INTTYPES_H
 #  include	<inttypes.h>
 #endif
-#ifdef HAVE_STDDEF_H
-#  include	<stddef.h>
-#endif
-#ifdef HAVE_STDINT_H
-#  include	<stdint.h>
-#endif
 
 #ifdef HAVE_SYS_IOCTL_H
 #  include	<sys/ioctl.h>
@@ -97,9 +101,6 @@
 #ifdef HAVE_ASSERT_H
 #  include      <assert.h>
 #endif
-#ifdef HAVE_CTYPE_H
-#  include      <ctype.h>
-#endif
 #ifdef HAVE_ERRNO_H
 #  include	<errno.h>
 #endif
@@ -127,19 +128,11 @@
 #ifdef HAVE_STDARG_H
 #  include      <stdarg.h>
 #endif
-#ifdef HAVE_STDIO_H
-#  include	<stdio.h>
-#endif
-#ifdef HAVE_STDLIB_H
-#  include	<stdlib.h>
-#else
-#  ifdef HAVE_MALLOC_H
-#    include	<malloc.h>
-#  endif
-#endif
-#ifdef HAVE_STRING_H
-#  include	<string.h>
+
+#ifdef HAVE_MALLOC_H
+#  include	<malloc.h>
 #endif
+
 #ifdef HAVE_STRINGS_H
 #  include	<strings.h>
 #endif
@@ -149,9 +142,6 @@
 #ifdef HAVE_SYSLOG_H
 #  include      <syslog.h>
 #endif
-#ifdef HAVE_UNISTD_H
-#  include      <unistd.h>
-#endif
 #ifdef HAVE_WCHAR_H
 #  include	<wchar.h>
 #endif