Remove traces of BeOS.

Commit 15abc7788e tolerated namespace pollution from BeOS system
headers.  Commit 44f902122 de-supported BeOS.  Since that stuff didn't
make it into the Meson build system, synchronize by removing from
configure.

Author: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (the idea, not the patch)
Discussion: https://postgr.es/m/ME3P282MB3166F9D1F71F787929C0C7E7B6312%40ME3P282MB3166.AUSP282.PROD.OUTLOOK.COM

src/interfaces/ecpg/include/ecpg_config.h.in

@@ -1,9 +1,6 @@
 /* Define to 1 to build client libraries as thread-safe code. */
 #define ENABLE_THREAD_SAFETY 1
 
-/* Define to 1 if the system has the type `int64'. */
-#undef HAVE_INT64
-
 /* Define to 1 if `long int' works and is 64 bits. */
 #undef HAVE_LONG_INT_64
 

src/interfaces/ecpg/include/meson.build

@@ -3,7 +3,6 @@
 ecpg_inc = include_directories('.')
 
 ecpg_conf_keys = [
-  'HAVE_INT64',
   'HAVE_LONG_INT_64',
   'HAVE_LONG_LONG_INT_64',
   'PG_USE_STDBOOL',

src/interfaces/ecpg/include/pgtypes_interval.h

@@ -9,13 +9,9 @@
 #ifndef C_H
 
 #ifdef HAVE_LONG_INT_64
-#ifndef HAVE_INT64
 typedef long int int64;
-#endif
 #elif defined(HAVE_LONG_LONG_INT_64)
-#ifndef HAVE_INT64
 typedef long long int int64;
-#endif
 #else
 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
 #error must have a working 64-bit integer datatype