Improve autofiles checksum check

autofiles.sums

@@ -1,7 +1,7 @@
-778da79a0593929b27db80016877d550  configure.ac
-d16a8e8947744745887520e331e59e39  m4/ax_random_device.m4
-2cc70ef55adb11e355f6e8c30dcab090  m4/libtool.m4
-064af1799febaa676203302bbf359180  m4/ltoptions.m4
-fa2891f9060865871cbbaa1c6e2d96f4  m4/ltsugar.m4
-d936fd6b2025c9b5322f826117d7f30c  m4/ltversion.m4
-22aa295bf5320aec7fba6756ff11058a  m4/lt~obsolete.m4
+9e7830c08cda9f1ffcbc6e6cce79e58dd6d8de5f6b9a889067c816b23f463025  configure.ac
+35bc5c645dc42d47f2daeea06f8f3e767c8a1aee6a35eb2b4854fd2ce66c3413  m4/ax_random_device.m4
+37f8897d5f68d7d484e5457832a8f190ddb7507fa2a467cb7ee2be40a4364643  m4/libtool.m4
+e77ebba8361b36f14b4d0927173a034b98c5d05049697a9ded84d85eb99a7990  m4/ltoptions.m4
+5a6735cda60e0ba0d1b706c0ef648f5d096298da46daefd9cdecdb6a0f4584d3  m4/ltsugar.m4
+a27b754709de61575197bf5a980696c98ae49da3f92f0de8ee7f42dd543b7465  m4/ltversion.m4
+26fa3285c35dd6ab00ed1e466ba92a17e4655e01897731ec18a587a4cf5e4f8d  m4/lt~obsolete.m4

autogen.sh

@@ -3,4 +3,4 @@ set -e
 aclocal -I m4
 autoheader
 autoconf
-md5sum configure.ac m4/* >| autofiles.sums
+sha256sum configure.ac m4/* >| autofiles.sums

configure

@@ -698,7 +698,7 @@ CPPFLAGS
 LDFLAGS
 CFLAGS
 CC
-MD5SUM
+SHA256SUM
 ACLOCAL
 AUTOHEADER
 AUTOCONF
@@ -2564,15 +2564,15 @@ $as_echo "no" >&6; }
 fi
 
 
-# Extract the first word of "md5sum", so it can be a program name with args.
-set dummy md5sum; ac_word=$2
+# Extract the first word of "sha256sum", so it can be a program name with args.
+set dummy sha256sum; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_MD5SUM+:} false; then :
+if ${ac_cv_prog_SHA256SUM+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  if test -n "$MD5SUM"; then
-  ac_cv_prog_MD5SUM="$MD5SUM" # Let the user override the test.
+  if test -n "$SHA256SUM"; then
+  ac_cv_prog_SHA256SUM="$SHA256SUM" # Let the user override the test.
 else
 as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
 for as_dir in $PATH
@@ -2581,29 +2581,29 @@ do
   test -z "$as_dir" && as_dir=.
     for ac_exec_ext in '' $ac_executable_extensions; do
   if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_MD5SUM="1"
+    ac_cv_prog_SHA256SUM="1"
     $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
     break 2
   fi
 done
   done
 IFS=$as_save_IFS
 
-  test -z "$ac_cv_prog_MD5SUM" && ac_cv_prog_MD5SUM="0"
+  test -z "$ac_cv_prog_SHA256SUM" && ac_cv_prog_SHA256SUM="0"
 fi
 fi
-MD5SUM=$ac_cv_prog_MD5SUM
-if test -n "$MD5SUM"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MD5SUM" >&5
-$as_echo "$MD5SUM" >&6; }
+SHA256SUM=$ac_cv_prog_SHA256SUM
+if test -n "$SHA256SUM"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $SHA256SUM" >&5
+$as_echo "$SHA256SUM" >&6; }
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
 fi
 
 
-if test "$AUTOCONF$AUTOHEADER$ACLOCAL$MD5SUM" = "1111"; then
-   if ! md5sum configure.ac m4/* | diff -w - autofiles.sums; then
+if test "$AUTOCONF$AUTOHEADER$ACLOCAL$SHA256SUM" = "1111"; then
+   if ! sha256sum -c autofiles.sums; then
        as_fn_error $? "autofiles are autodated; rerun autogen.sh" "$LINENO" 5
    fi
 fi

configure.ac

@@ -16,9 +16,9 @@ AC_CONFIG_HEADERS([libqpdf/qpdf/qpdf-config.h])
 AC_CHECK_PROG(AUTOCONF,autoconf,1,0)
 AC_CHECK_PROG(AUTOHEADER,autoheader,1,0)
 AC_CHECK_PROG(ACLOCAL,aclocal,1,0)
-AC_CHECK_PROG(MD5SUM,md5sum,1,0)
-if test "$AUTOCONF$AUTOHEADER$ACLOCAL$MD5SUM" = "1111"; then
-   if ! md5sum configure.ac m4/* | diff -w - autofiles.sums; then
+AC_CHECK_PROG(SHA256SUM,sha256sum,1,0)
+if test "$AUTOCONF$AUTOHEADER$ACLOCAL$SHA256SUM" = "1111"; then
+   if ! sha256sum -c autofiles.sums; then
        AC_MSG_ERROR(autofiles are autodated; rerun autogen.sh)
    fi
 fi