Autoconf: Do not check for C99 uintptr_t. [skip appveyor]

At the time of commit 09b639a in 2015 C99 was not a requirement yet, so
the use of AC_TYPE_UINTPTR_T was necessary.  However, CMake since its
introduction in 2018 has not been checking for uintptr_t, which proves
that by now all supported platforms have the type and the Autoconf check
is obsolete.

Author: infrastation

cmakeconfig.h.in

@@ -165,9 +165,6 @@
 /* Define to 1 if the system has the type `struct ether_addr'. */
 #cmakedefine HAVE_STRUCT_ETHER_ADDR 1
 
-/* Define to 1 if the system has the type `uintptr_t'. */
-#cmakedefine HAVE_UINTPTR_T 1
-
 /* Define to 1 if you have the `vfork' function. */
 #cmakedefine HAVE_VFORK 1
 
@@ -236,7 +233,3 @@
 
 /* Define to `uint8_t' if u_int8_t not defined. */
 #cmakedefine u_int8_t 1
-
-/* Define to the type of an unsigned integer type wide enough to hold a
-   pointer, if such a type exists, and if the system does not define it. */
-#cmakedefine uintptr_t 1

configure.ac

@@ -725,12 +725,6 @@ solaris*)
 	;;
 esac
 
-#
-# Make sure we have a definition for C99's uintptr_t (regardless of
-# whether the environment is a C99 environment or not).
-#
-AC_TYPE_UINTPTR_T
-
 savedcppflags="$CPPFLAGS"
 CPPFLAGS="$CPPFLAGS $V_INCLS"