configure: drop detection of stdint.h and inttypes.h

The current code uses macros from inttypes.h. There is no point in
detecting and selecting between stdint.h and inttypes.h as the latter is
always needed.

configure

@@ -595,14 +595,6 @@ else
   fi
 fi
   
-if test_code '<stdint.h>' 'stdint.h' '' '' ''; then
-  add_def HAVE_STDINT_H
-fi
-
-if test_code '<inttypes.h>' 'inttypes.h' '' '' ''; then
-  add_def HAVE_INTTYPES_H
-fi
-
 if test_code 'struct in_pktinfo' 'sys/socket.h netinet/in.h' '' '' '
   struct in_pktinfo ipi;
   return sizeof (ipi.ipi_spec_dst.s_addr) + IP_PKTINFO;'

sysincl.h

@@ -36,6 +36,7 @@
 #include <float.h>
 #include <glob.h>
 #include <grp.h>
+#include <inttypes.h>
 #include <math.h>
 #include <netdb.h>
 #include <netinet/in.h>
@@ -63,14 +64,6 @@
 #include <sys/timex.h>
 #endif
 
-#ifdef HAVE_INTTYPES_H
-#include <inttypes.h>
-#elif HAVE_STDINT_H
-#include <stdint.h>
-#else
-/* Tough */
-#endif
-
 #ifdef FEAT_IPV6
 /* For inet_ntop() */
 #include <arpa/inet.h>