diff -u -r ../zip30/unix/configure ./unix/configure
--- ../zip30/unix/configure	2008-06-20 04:32:20.000000000 +0100
+++ ./unix/configure	2020-07-12 06:48:24.521323595 +0100
@@ -348,55 +348,10 @@
 echo " tests if this OS uses 16-bit UIDs/GIDs and so if the old 16-bit storage"
 echo " should also be used for backward compatibility.)"
 # Added 2008-04-15 CS
-cat > conftest.c << _EOF_
-# define _LARGEFILE_SOURCE          /* some OSes need this for fseeko */
-# define _LARGEFILE64_SOURCE
-# define _FILE_OFFSET_BITS 64       /* select default interface as 64 bit */
-# define _LARGE_FILES               /* some OSes need this for 64-bit off_t */
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <stdio.h>
-int main()
-{
-  struct stat s;
-
-  printf("  s.st_uid is %u bytes\n", sizeof(s.st_uid));
-  printf("  s.st_gid is %u bytes\n", sizeof(s.st_gid));
-
-  /* see if have 16-bit UID */
-  if (sizeof(s.st_uid) != 2) {
-    return 1;
-  }
-  /* see if have 16-bit GID */
-  if (sizeof(s.st_gid) != 2) {
-    return 2;
-  }
-  return 3;
-}
-_EOF_
-# compile it
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-if [ $? -ne 0 ]; then
-  echo -- UID/GID test failed on compile - disabling old 16-bit UID/GID support
-  CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-else
-# run it
-  ./conftest
-  r=$?
-  if [ $r -eq 1 ]; then
+echo '  s.st_uid is 4 bytes'
+echo '  s.st_gid is 4 bytes'
     echo -- UID not 2 bytes - disabling old 16-bit UID/GID support
     CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  elif [ $r -eq 2 ]; then
-    echo -- GID not 2 bytes - disabling old 16-bit UID/GID support
-    CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  elif [ $r -eq 3 ]; then
-    echo -- 16-bit UIDs and GIDs - keeping old 16-bit UID/GID support
-  else
-    echo -- test failed - conftest returned $r - disabling old 16-bit UID/GID support
-    CFLAGS="${CFLAGS} -DUIDGID_NOT_16BIT"
-  fi
-fi
 
 
 # Now we set the 64-bit file environment and check the size of off_t
@@ -404,50 +359,9 @@
 # Revised 8/12/2004 EG
 
 echo Check for Large File Support
-cat > conftest.c << _EOF_
-# define _LARGEFILE_SOURCE       /* some OSes need this for fseeko */
-# define _LARGEFILE64_SOURCE
-# define _FILE_OFFSET_BITS 64       /* select default interface as 64 bit */
-# define _LARGE_FILES        /* some OSes need this for 64-bit off_t */
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <stdio.h>
-int main()
-{
-  off_t offset;
-  struct stat s;
-  /* see if have 64-bit off_t */
-  if (sizeof(offset) < 8)
-    return 1;
-  printf("  off_t is %d bytes\n", sizeof(off_t));
-  /* see if have 64-bit stat */
-  if (sizeof(s.st_size) < 8) {
-    printf("  s.st_size is %d bytes\n", sizeof(s.st_size));
-    return 2;
-  }
-  return 3;
-}
-_EOF_
-# compile it
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-if [ $? -ne 0 ]; then
-  echo -- no Large File Support
-else
-# run it
-  ./conftest
-  r=$?
-  if [ $r -eq 1 ]; then
-    echo -- no Large File Support - no 64-bit off_t
-  elif [ $r -eq 2 ]; then
-    echo -- no Large File Support - no 64-bit stat
-  elif [ $r -eq 3 ]; then
+echo '  off_t is 8 bytes'
     echo -- yes we have Large File Support!
     CFLAGS="${CFLAGS} -DLARGE_FILE_SUPPORT"
-  else
-    echo -- no Large File Support - conftest returned $r
-  fi
-fi
 
 
 # Check for wide char for Unicode support
@@ -509,83 +423,6 @@
 # Check for missing functions
 # add NO_'function_name' to flags if missing
 
-for func in rmdir strchr strrchr rename mktemp mktime mkstemp
-do
-  echo Check for $func
-  echo "int main(){ $func(); return 0; }" > conftest.c
-  $CC $BFLAG -o conftest conftest.c >/dev/null 2>/dev/null
-  [ $? -ne 0 ] && CFLAGS="${CFLAGS} -DNO_`echo $func | tr '[a-z]' '[A-Z]'`"
-done
-
-
-echo Check for memset
-echo "int main(){ char k; memset(&k,0,0); return 0; }" > conftest.c
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-[ $? -ne 0 ] && CFLAGS="${CFLAGS} -DZMEM"
-
-
-echo Check for memmove
-cat > conftest.c << _EOF_
-#include <string.h>
-int main() { int a; int b = 0; memmove( &a, &b, sizeof( a)); return a; }
-_EOF_
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-[ $? -ne 0 ] && CFLAGS="${CFLAGS} -DNEED_MEMMOVE"
-
-
-echo Check for strerror
-cat > conftest.c << _EOF_
-#include <string.h>
-int main() { strerror( 0); return 0; }
-_EOF_
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-[ $? -ne 0 ] && CFLAGS="${CFLAGS} -DNEED_STRERROR"
-
-echo Check for errno declaration
-cat > conftest.c << _EOF_
-#include <errno.h>
-main()
-{
-  errno = 0;
-  return 0;
-}
-_EOF_
-$CC $CFLAGS -c conftest.c >/dev/null 2>/dev/null
-[ $? -ne 0 ] && CFLAGS="${CFLAGS} -DNO_ERRNO"
-
-
-echo Check for directory libraries
-cat > conftest.c << _EOF_
-int main() { return closedir(opendir(".")); }
-_EOF_
-
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-if [ $? -ne 0 ]; then
-  OPT=""
-  for lib in ndir dir ucb bsd BSD PW x dirent
-  do
-    $CC -o conftest conftest.c -l$lib >/dev/null 2>/dev/null
-    [ $? -eq 0 ] && OPT=-l$lib && break
-  done
-  if [ ${OPT} ]; then
-    LFLAGS2="${LFLAGS2} ${OPT}"
-  else
-    CFLAGS="${CFLAGS} -DNO_DIR"
-  fi
-fi
-
-
-# Dynix/ptx 1.3 needed this
-
-echo Check for readlink
-echo "int main(){ return readlink(); }" > conftest.c
-$CC -o conftest conftest.c >/dev/null 2>/dev/null
-if [ $? -ne 0 ]; then
-  $CC -o conftest conftest.c -lseq >/dev/null 2>/dev/null
-  [ $? -eq 0 ] && LFLAGS2="${LFLAGS2} -lseq"
-fi
-
-
 echo Check for directory include file
 OPT=""
 for inc in dirent.h sys/ndir.h ndir.h sys/dir.h