diff --git a/ChangeLog b/ChangeLog
index 23d653768..023444a2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2004-03-15  Paolo Bonzini  <bonzini@gnu.org>
+            Nathanael Nerode  <neroden@gcc.gnu.org>
+
+	* configure.in (DEFAULT_YACC, DEFAULT_M4, DEFAULT_LEX):
+        Set with AC_CHECK_PROGS.
+	* configure.in: Fix comment typo from last patch.
+	* configure: Regenerate.
+
 2004-03-15  Nathanael Nerode  <neroden@gcc.gnu.org>
 
 	* Makefile.tpl: Introduce experimental top level bootstrap support.
diff --git a/configure b/configure
index 0efa37b6d..90f42d496 100755
--- a/configure
+++ b/configure
@@ -2173,7 +2173,7 @@ else
 fi
 
 
-# By default, C is the only stage 1 langauge.
+# By default, C is the only stage 1 language.
 stage1_languages=c
 
 
@@ -2600,62 +2600,114 @@ esac
 tooldir='${exec_prefix}'/${target_alias}
 build_tooldir=${tooldir}
 
-# Generate a default definition for YACC.  This is used if the makefile can't
-# locate bison or byacc in objdir.
-
-for prog in 'bison -y' byacc yacc
+# Generate default definitions for YACC, M4, LEX.  These are used if the
+# Makefile can't locate these programs in objdir.
+MISSING=`cd $ac_aux_dir && ${PWDCMD-pwd}`/missing
+for ac_prog in 'bison -y' byacc yacc
 do
-  set dummy $prog; tmp=$2
-  IFS="${IFS= 	}"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_YACC="$prog"
+# Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
+echo "configure:2612: checking for $ac_word" >&5
+if eval "test \"`echo '$''{'ac_cv_prog_DEFAULT_YACC'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  if test -n "$DEFAULT_YACC"; then
+  ac_cv_prog_DEFAULT_YACC="$DEFAULT_YACC" # Let the user override the test.
+else
+  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS=":"
+  ac_dummy="$PATH"
+  for ac_dir in $ac_dummy; do
+    test -z "$ac_dir" && ac_dir=.
+    if test -f $ac_dir/$ac_word; then
+      ac_cv_prog_DEFAULT_YACC="$ac_prog"
       break
     fi
   done
-  IFS="$save_ifs"
+  IFS="$ac_save_ifs"
+fi
+fi
+DEFAULT_YACC="$ac_cv_prog_DEFAULT_YACC"
+if test -n "$DEFAULT_YACC"; then
+  echo "$ac_t""$DEFAULT_YACC" 1>&6
+else
+  echo "$ac_t""no" 1>&6
+fi
 
-  test -n "$DEFAULT_YACC" && break
+test -n "$DEFAULT_YACC" && break
 done
+test -n "$DEFAULT_YACC" || DEFAULT_YACC="$MISSING bison"
 
-# Generate a default definition for M4.  This is used if the makefile can't
-# locate m4 in objdir.
-
-for prog in gm4 gnum4 m4
+for ac_prog in gm4 gnum4 m4
 do
-  set dummy $prog; tmp=$2
-  IFS="${IFS=   }"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_M4="$prog"
+# Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
+echo "configure:2647: checking for $ac_word" >&5
+if eval "test \"`echo '$''{'ac_cv_prog_DEFAULT_M4'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  if test -n "$DEFAULT_M4"; then
+  ac_cv_prog_DEFAULT_M4="$DEFAULT_M4" # Let the user override the test.
+else
+  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS=":"
+  ac_dummy="$PATH"
+  for ac_dir in $ac_dummy; do
+    test -z "$ac_dir" && ac_dir=.
+    if test -f $ac_dir/$ac_word; then
+      ac_cv_prog_DEFAULT_M4="$ac_prog"
       break
     fi
   done
-  IFS="$save_ifs"
+  IFS="$ac_save_ifs"
+fi
+fi
+DEFAULT_M4="$ac_cv_prog_DEFAULT_M4"
+if test -n "$DEFAULT_M4"; then
+  echo "$ac_t""$DEFAULT_M4" 1>&6
+else
+  echo "$ac_t""no" 1>&6
+fi
 
-  test -n "$DEFAULT_M4" && break
+test -n "$DEFAULT_M4" && break
 done
+test -n "$DEFAULT_M4" || DEFAULT_M4="$MISSING m4"
 
-# Generate a default definition for LEX.  This is used if the makefile can't
-# locate flex in objdir.
-
-for prog in flex lex
+for ac_prog in flex lex
 do
-  set dummy $prog; tmp=$2
-  IFS="${IFS= 	}"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_LEX="$prog"
+# Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
+echo "configure:2682: checking for $ac_word" >&5
+if eval "test \"`echo '$''{'ac_cv_prog_DEFAULT_LEX'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  if test -n "$DEFAULT_LEX"; then
+  ac_cv_prog_DEFAULT_LEX="$DEFAULT_LEX" # Let the user override the test.
+else
+  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS=":"
+  ac_dummy="$PATH"
+  for ac_dir in $ac_dummy; do
+    test -z "$ac_dir" && ac_dir=.
+    if test -f $ac_dir/$ac_word; then
+      ac_cv_prog_DEFAULT_LEX="$ac_prog"
       break
     fi
   done
-  IFS="$save_ifs"
+  IFS="$ac_save_ifs"
+fi
+fi
+DEFAULT_LEX="$ac_cv_prog_DEFAULT_LEX"
+if test -n "$DEFAULT_LEX"; then
+  echo "$ac_t""$DEFAULT_LEX" 1>&6
+else
+  echo "$ac_t""no" 1>&6
+fi
 
-  test -n "$DEFAULT_LEX" && break
+test -n "$DEFAULT_LEX" && break
 done
+test -n "$DEFAULT_LEX" || DEFAULT_LEX="$MISSING flex"
+
 
 # FIXME Should this be done recursively ??? (Useful for e.g. gdbtest)
 # Set up the list of links to be made.
@@ -3234,7 +3286,7 @@ test -n "$target_alias" && ncn_target_tool_prefix=$target_alias-
   # Extract the first word of "${ncn_tool_prefix}ar", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}ar; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3238: checking for $ac_word" >&5
+echo "configure:3290: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_AR'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3267,7 +3319,7 @@ if test -z "$ac_cv_prog_AR" ; then
     # Extract the first word of "ar", so it can be a program name with args.
 set dummy ar; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3271: checking for $ac_word" >&5
+echo "configure:3323: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_AR'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3306,7 +3358,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}as", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}as; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3310: checking for $ac_word" >&5
+echo "configure:3362: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_AS'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3339,7 +3391,7 @@ if test -z "$ac_cv_prog_AS" ; then
     # Extract the first word of "as", so it can be a program name with args.
 set dummy as; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3343: checking for $ac_word" >&5
+echo "configure:3395: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_AS'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3378,7 +3430,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}dlltool", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}dlltool; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3382: checking for $ac_word" >&5
+echo "configure:3434: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_DLLTOOL'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3411,7 +3463,7 @@ if test -z "$ac_cv_prog_DLLTOOL" ; then
     # Extract the first word of "dlltool", so it can be a program name with args.
 set dummy dlltool; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3415: checking for $ac_word" >&5
+echo "configure:3467: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_DLLTOOL'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3450,7 +3502,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}ld", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}ld; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3454: checking for $ac_word" >&5
+echo "configure:3506: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_LD'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3483,7 +3535,7 @@ if test -z "$ac_cv_prog_LD" ; then
     # Extract the first word of "ld", so it can be a program name with args.
 set dummy ld; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3487: checking for $ac_word" >&5
+echo "configure:3539: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_LD'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3522,7 +3574,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}nm", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}nm; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3526: checking for $ac_word" >&5
+echo "configure:3578: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_NM'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3555,7 +3607,7 @@ if test -z "$ac_cv_prog_NM" ; then
     # Extract the first word of "nm", so it can be a program name with args.
 set dummy nm; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3559: checking for $ac_word" >&5
+echo "configure:3611: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_NM'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3594,7 +3646,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}ranlib", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}ranlib; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3598: checking for $ac_word" >&5
+echo "configure:3650: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_RANLIB'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3627,7 +3679,7 @@ if test -z "$ac_cv_prog_RANLIB" ; then
     # Extract the first word of "ranlib", so it can be a program name with args.
 set dummy ranlib; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3631: checking for $ac_word" >&5
+echo "configure:3683: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_RANLIB'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3666,7 +3718,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}windres", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}windres; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3670: checking for $ac_word" >&5
+echo "configure:3722: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_WINDRES'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3699,7 +3751,7 @@ if test -z "$ac_cv_prog_WINDRES" ; then
     # Extract the first word of "windres", so it can be a program name with args.
 set dummy windres; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3703: checking for $ac_word" >&5
+echo "configure:3755: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_WINDRES'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3738,7 +3790,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}objcopy", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}objcopy; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3742: checking for $ac_word" >&5
+echo "configure:3794: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_OBJCOPY'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3771,7 +3823,7 @@ if test -z "$ac_cv_prog_OBJCOPY" ; then
     # Extract the first word of "objcopy", so it can be a program name with args.
 set dummy objcopy; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3775: checking for $ac_word" >&5
+echo "configure:3827: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_OBJCOPY'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3810,7 +3862,7 @@ fi
   # Extract the first word of "${ncn_tool_prefix}objdump", so it can be a program name with args.
 set dummy ${ncn_tool_prefix}objdump; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3814: checking for $ac_word" >&5
+echo "configure:3866: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_OBJDUMP'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3843,7 +3895,7 @@ if test -z "$ac_cv_prog_OBJDUMP" ; then
     # Extract the first word of "objdump", so it can be a program name with args.
 set dummy objdump; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3847: checking for $ac_word" >&5
+echo "configure:3899: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_OBJDUMP'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3892,7 +3944,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}ar", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}ar; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3896: checking for $ac_word" >&5
+echo "configure:3948: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_AR_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3925,7 +3977,7 @@ if test -z "$ac_cv_prog_AR_FOR_TARGET" ; then
     # Extract the first word of "ar", so it can be a program name with args.
 set dummy ar; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3929: checking for $ac_word" >&5
+echo "configure:3981: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_AR_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3964,7 +4016,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}as", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}as; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:3968: checking for $ac_word" >&5
+echo "configure:4020: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_AS_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -3997,7 +4049,7 @@ if test -z "$ac_cv_prog_AS_FOR_TARGET" ; then
     # Extract the first word of "as", so it can be a program name with args.
 set dummy as; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4001: checking for $ac_word" >&5
+echo "configure:4053: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_AS_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4036,7 +4088,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}dlltool", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}dlltool; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4040: checking for $ac_word" >&5
+echo "configure:4092: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_DLLTOOL_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4069,7 +4121,7 @@ if test -z "$ac_cv_prog_DLLTOOL_FOR_TARGET" ; then
     # Extract the first word of "dlltool", so it can be a program name with args.
 set dummy dlltool; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4073: checking for $ac_word" >&5
+echo "configure:4125: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_DLLTOOL_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4108,7 +4160,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}ld", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}ld; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4112: checking for $ac_word" >&5
+echo "configure:4164: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_LD_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4141,7 +4193,7 @@ if test -z "$ac_cv_prog_LD_FOR_TARGET" ; then
     # Extract the first word of "ld", so it can be a program name with args.
 set dummy ld; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4145: checking for $ac_word" >&5
+echo "configure:4197: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_LD_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4180,7 +4232,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}nm", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}nm; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4184: checking for $ac_word" >&5
+echo "configure:4236: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_NM_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4213,7 +4265,7 @@ if test -z "$ac_cv_prog_NM_FOR_TARGET" ; then
     # Extract the first word of "nm", so it can be a program name with args.
 set dummy nm; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4217: checking for $ac_word" >&5
+echo "configure:4269: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_NM_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4252,7 +4304,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}ranlib", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}ranlib; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4256: checking for $ac_word" >&5
+echo "configure:4308: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_RANLIB_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4285,7 +4337,7 @@ if test -z "$ac_cv_prog_RANLIB_FOR_TARGET" ; then
     # Extract the first word of "ranlib", so it can be a program name with args.
 set dummy ranlib; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4289: checking for $ac_word" >&5
+echo "configure:4341: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_RANLIB_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4324,7 +4376,7 @@ fi
   # Extract the first word of "${ncn_target_tool_prefix}windres", so it can be a program name with args.
 set dummy ${ncn_target_tool_prefix}windres; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4328: checking for $ac_word" >&5
+echo "configure:4380: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_WINDRES_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4357,7 +4409,7 @@ if test -z "$ac_cv_prog_WINDRES_FOR_TARGET" ; then
     # Extract the first word of "windres", so it can be a program name with args.
 set dummy windres; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:4361: checking for $ac_word" >&5
+echo "configure:4413: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_ncn_cv_WINDRES_FOR_TARGET'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -4424,7 +4476,7 @@ RANLIB_FOR_TARGET=${RANLIB_FOR_TARGET}${extra_ranlibflags_for_target}
 NM_FOR_TARGET=${NM_FOR_TARGET}${extra_nmflags_for_target}
 
 echo $ac_n "checking whether to enable maintainer-specific portions of Makefiles""... $ac_c" 1>&6
-echo "configure:4428: checking whether to enable maintainer-specific portions of Makefiles" >&5
+echo "configure:4480: checking whether to enable maintainer-specific portions of Makefiles" >&5
 # Check whether --enable-maintainer-mode or --disable-maintainer-mode was given.
 if test "${enable_maintainer_mode+set}" = set; then
   enableval="$enable_maintainer_mode"
@@ -4653,6 +4705,9 @@ s%@target_subdir@%$target_subdir%g
 s%@CC@%$CC%g
 s%@GNATBIND@%$GNATBIND%g
 s%@stage1_languages@%$stage1_languages%g
+s%@DEFAULT_YACC@%$DEFAULT_YACC%g
+s%@DEFAULT_M4@%$DEFAULT_M4%g
+s%@DEFAULT_LEX@%$DEFAULT_LEX%g
 /@maybe_dependencies@/r $maybe_dependencies
 s%@maybe_dependencies@%%g
 /@serialization_dependencies@/r $serialization_dependencies
@@ -4710,9 +4765,6 @@ s%@OBJDUMP@%$OBJDUMP%g
 s%@ncn_cv_OBJDUMP@%$ncn_cv_OBJDUMP%g
 s%@CXX@%$CXX%g
 s%@CFLAGS_FOR_BUILD@%$CFLAGS_FOR_BUILD%g
-s%@DEFAULT_YACC@%$DEFAULT_YACC%g
-s%@DEFAULT_LEX@%$DEFAULT_LEX%g
-s%@DEFAULT_M4@%$DEFAULT_M4%g
 s%@AR_FOR_TARGET@%$AR_FOR_TARGET%g
 s%@ncn_cv_AR_FOR_TARGET@%$ncn_cv_AR_FOR_TARGET%g
 s%@AS_FOR_TARGET@%$AS_FOR_TARGET%g
diff --git a/configure.in b/configure.in
index a5ba6e2ca..833de1f50 100644
--- a/configure.in
+++ b/configure.in
@@ -1070,7 +1070,7 @@ fi
 
 ACX_PROG_GNAT
 
-# By default, C is the only stage 1 langauge.
+# By default, C is the only stage 1 language.
 stage1_languages=c
 AC_SUBST(stage1_languages)
 
@@ -1497,62 +1497,12 @@ esac
 tooldir='${exec_prefix}'/${target_alias}
 build_tooldir=${tooldir}
 
-# Generate a default definition for YACC.  This is used if the makefile can't
-# locate bison or byacc in objdir.
-
-for prog in 'bison -y' byacc yacc
-do
-  set dummy $prog; tmp=$2
-  IFS="${IFS= 	}"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_YACC="$prog"
-      break
-    fi
-  done
-  IFS="$save_ifs"
-
-  test -n "$DEFAULT_YACC" && break
-done
-
-# Generate a default definition for M4.  This is used if the makefile can't
-# locate m4 in objdir.
-
-for prog in gm4 gnum4 m4
-do
-  set dummy $prog; tmp=$2
-  IFS="${IFS=   }"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_M4="$prog"
-      break
-    fi
-  done
-  IFS="$save_ifs"
-
-  test -n "$DEFAULT_M4" && break
-done
-
-# Generate a default definition for LEX.  This is used if the makefile can't
-# locate flex in objdir.
-
-for prog in flex lex
-do
-  set dummy $prog; tmp=$2
-  IFS="${IFS= 	}"; save_ifs="$IFS"; IFS="${IFS}:"
-  for dir in $PATH; do
-    test -z "$dir" && dir=.
-    if test -f $dir/$tmp; then
-      DEFAULT_LEX="$prog"
-      break
-    fi
-  done
-  IFS="$save_ifs"
-
-  test -n "$DEFAULT_LEX" && break
-done
+# Generate default definitions for YACC, M4, LEX.  These are used if the
+# Makefile can't locate these programs in objdir.
+MISSING=`cd $ac_aux_dir && ${PWDCMD-pwd}`/missing
+AC_CHECK_PROGS([DEFAULT_YACC], ['bison -y' byacc yacc], [$MISSING bison])
+AC_CHECK_PROGS([DEFAULT_M4], [gm4 gnum4 m4], [$MISSING m4])
+AC_CHECK_PROGS([DEFAULT_LEX], [flex lex], [$MISSING flex])
 
 # FIXME Should this be done recursively ??? (Useful for e.g. gdbtest)
 # Set up the list of links to be made.