deleted file mode 100644
--- a/m4/const.m4
+++ /dev/null
@@ -1,66 +0,0 @@
-#serial 1
-
-dnl Just like AC_C_CONST from autoconf-2.12, but with an initializer
-dnl for `charset x' and with
-dnl   AC_DEFINE(const, )
-dnl changed to
-dnl   AC_DEFINE_UNQUOTED(const, [/* empty */])
-dnl to avoid this warning:
-dnl   [...]/m4: Warning: Excess arguments to built-in `define' ignored
-
-undefine([AC_C_CONST])
-AC_DEFUN(AC_C_CONST,
-[dnl This message is consistent in form with the other checking messages,
-dnl and with the result message.
-AC_CACHE_CHECK([for working const], ac_cv_c_const,
-[AC_TRY_COMPILE(,
-changequote(<<, >>)dnl
-<<
-/* Ultrix mips cc rejects this.  */
-typedef int charset[2]; const charset x = {0, 0};
-/* SunOS 4.1.1 cc rejects this.  */
-char const *const *ccp;
-char **p;
-/* NEC SVR4.0.2 mips cc rejects this.  */
-struct point {int x, y;};
-static struct point const zero = {0,0};
-/* AIX XL C 1.02.0.0 rejects this.
-   It does not let you subtract one const X* pointer from another in an arm
-   of an if-expression whose if-part is not a constant expression */
-const char *g = "string";
-ccp = &g + (g ? g-g : 0);
-/* HPUX 7.0 cc rejects these. */
-++ccp;
-p = (char**) ccp;
-ccp = (char const *const *) p;
-{ /* SCO 3.2v4 cc rejects this.  */
-  char *t;
-  char const *s = 0 ? (char *) 0 : (char const *) 0;
-
-  *t++ = 0;
-}
-{ /* Someone thinks the Sun supposedly-ANSI compiler will reject this.  */
-  int x[] = {25, 17};
-  const int *foo = &x[0];
-  ++foo;
-}
-{ /* Sun SC1.0 ANSI compiler rejects this -- but not the above. */
-  typedef const int *iptr;
-  iptr p = 0;
-  ++p;
-}
-{ /* AIX XL C 1.02.0.0 rejects this saying
-     "k.c", line 2.27: 1506-025 (S) Operand must be a modifiable lvalue. */
-  struct s { int j; const int *ap[3]; };
-  struct s *b; b->j = 5;
-}
-{ /* ULTRIX-32 V3.1 (Rev 9) vcc rejects this */
-  const int foo = 10;
-}
->>,
-changequote([, ])dnl
-ac_cv_c_const=yes, ac_cv_c_const=no)])
-if test $ac_cv_c_const = no; then
-  AC_DEFINE_UNQUOTED(const, [/* empty */])
-fi
-])