PATCH: spurious error in config.status when no AC_DEFINEs happen

[Paolo Bonzini]

If a configure script does no AC_DEFINEs, the config.status
produced by 2.50 emits a spurious "sed: confdefs.h not found"
error.  This patch fixes the bug by ensuring that confdefs.h
exists when sed is invoked.

Paolo


*** acgeneral.m4.orig Mon Jun 18 13:29:56 2001
--- acgeneral.m4 Mon Jun 18 13:34:05 2001
***************
*** 1455,1460 ****
--- 1455,1463 ----
                            [^ *\(#.*\)?
  ]),
                ['], ['"'"']) >&AS_MESSAGE_LOG_FD
+
+   # Ensure confdefs.h exists
+   echo >> confdefs.h
    sed "/^$/d" confdefs.h >conftest.log
    if test -s conftest.log; then
      echo >&AS_MESSAGE_LOG_FD
***************
*** 3896,3901 ****
--- 3899,3907 ----
  # platform that uses two characters for line-breaks (e.g., DOS), tr
  # would break.
  ac_LF_and_DOT=`echo; echo .`
+
+ # Ensure confdefs.h exists
+ echo >> confdefs.h
  DEFS=`sed -n -f confdef2opt.sed confdefs.h | tr "$ac_LF_and_DOT" ' .'`
  rm -f confdef2opt.sed
  ]])# AC_OUTPUT_MAKE_DEFS