diff --git a/configure b/configure
index b899e6f9..be1ce90a 100755
--- a/configure
+++ b/configure
@@ -18795,7 +18795,7 @@ $as_echo "$as_me: executing $ac_file commands" >&6;}
 
   case $ac_file$ac_mode in
     "include/final/fconfig.h":C) ac_prefix_conf_OUT=`echo include/final/fconfig.h`
-ac_prefix_conf_DEF=`echo _$ac_prefix_conf_OUT | sed -e "y:abcdefghijklmnopqrstuvwxyz:ABCDEFGHIJKLMNOPQRSTUVWXYZ:" -e "s/[^abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ]/_/g"`
+ac_prefix_conf_DEF=`echo $ac_prefix_conf_OUT | sed -e "y:abcdefghijklmnopqrstuvwxyz:ABCDEFGHIJKLMNOPQRSTUVWXYZ:" -e "s/[^abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ]/_/g"`
 ac_prefix_conf_PKG=`echo F`
 ac_prefix_conf_LOW=`echo _$ac_prefix_conf_PKG | sed -e "y:ABCDEFGHIJKLMNOPQRSTUVWXYZ-:abcdefghijklmnopqrstuvwxyz_:"`
 ac_prefix_conf_UPP=`echo $ac_prefix_conf_PKG | sed -e "y:abcdefghijklmnopqrstuvwxyz-:ABCDEFGHIJKLMNOPQRSTUVWXYZ_:"  -e "/^[0123456789]/s/^/_/"`
@@ -18839,11 +18839,11 @@ $as_echo "$as_me: creating $ac_prefix_conf_OUT - prefix $ac_prefix_conf_UPP for
     # now executing _script on _DEF input to create _OUT output file
     echo "#ifndef $ac_prefix_conf_DEF"      >$tmp/pconfig.h
     echo "#define $ac_prefix_conf_DEF 1" >>$tmp/pconfig.h
-    echo ' ' >>$tmp/pconfig.h
+    echo '' >>$tmp/pconfig.h
     echo /'*' $ac_prefix_conf_OUT. Generated automatically at end of configure. '*'/ >>$tmp/pconfig.h
 
     sed -f conftest.prefix $ac_prefix_conf_INP >>$tmp/pconfig.h
-    echo ' ' >>$tmp/pconfig.h
+    echo '' >>$tmp/pconfig.h
     echo '/* once:' $ac_prefix_conf_DEF '*/' >>$tmp/pconfig.h
     echo "#endif" >>$tmp/pconfig.h
     if cmp -s $ac_prefix_conf_OUT $tmp/pconfig.h 2>/dev/null; then
diff --git a/include/final/fconfig.h b/include/final/fconfig.h
index f3dc2f90..1dee6909 100644
--- a/include/final/fconfig.h
+++ b/include/final/fconfig.h
@@ -1,6 +1,6 @@
-#ifndef _INCLUDE_FINAL_FCONFIG_H
-#define _INCLUDE_FINAL_FCONFIG_H 1
- 
+#ifndef INCLUDE_FINAL_FCONFIG_H
+#define INCLUDE_FINAL_FCONFIG_H 1
+
 /* include/final/fconfig.h. Generated automatically at end of configure. */
 /* config.h.  Generated from config.h.in by configure.  */
 /* config.h.in.  Generated from configure.ac by autoheader.  */
@@ -171,6 +171,6 @@
 #ifndef F_VERSION
 #define F_VERSION "0.3.0"
 #endif
- 
-/* once: _INCLUDE_FINAL_FCONFIG_H */
+
+/* once: INCLUDE_FINAL_FCONFIG_H */
 #endif
diff --git a/m4/ax_prefix_config_h.m4 b/m4/ax_prefix_config_h.m4
index c17563f4..5a3b2f92 100644
--- a/m4/ax_prefix_config_h.m4
+++ b/m4/ax_prefix_config_h.m4
@@ -129,7 +129,7 @@ AS_VAR_PUSHDEF([_INP],[ac_prefix_conf_INP])dnl
 m4_pushdef([_script],[conftest.prefix])dnl
 m4_pushdef([_symbol],[m4_cr_Letters[]m4_cr_digits[]_])dnl
 _OUT=`echo m4_default([$1], [$PACKAGE-config.h])`
-_DEF=`echo _$_OUT | sed -e "y:m4_cr_letters:m4_cr_LETTERS[]:" -e "s/@<:@^m4_cr_Letters@:>@/_/g"`
+_DEF=`echo $_OUT | sed -e "y:m4_cr_letters:m4_cr_LETTERS[]:" -e "s/@<:@^m4_cr_Letters@:>@/_/g"`
 _PKG=`echo m4_default([$2], [$PACKAGE])`
 _LOW=`echo _$_PKG | sed -e "y:m4_cr_LETTERS-:m4_cr_letters[]_:"`
 _UPP=`echo $_PKG | sed -e "y:m4_cr_letters-:m4_cr_LETTERS[]_:"  -e "/^@<:@m4_cr_digits@:>@/s/^/_/"`
@@ -172,11 +172,11 @@ else
     # now executing _script on _DEF input to create _OUT output file
     echo "@%:@ifndef $_DEF"      >$tmp/pconfig.h
     echo "@%:@def[]ine $_DEF 1" >>$tmp/pconfig.h
-    echo ' ' >>$tmp/pconfig.h
+    echo '' >>$tmp/pconfig.h
     echo /'*' $_OUT. Generated automatically at end of configure. '*'/ >>$tmp/pconfig.h
 
     sed -f _script $_INP >>$tmp/pconfig.h
-    echo ' ' >>$tmp/pconfig.h
+    echo '' >>$tmp/pconfig.h
     echo '/* once:' $_DEF '*/' >>$tmp/pconfig.h
     echo "@%:@endif" >>$tmp/pconfig.h
     if cmp -s $_OUT $tmp/pconfig.h 2>/dev/null; then