configure: Fix spelling in comment and rework the comment

* Replace vill -> will.

* Comment was formatted to make it more readable
  and to conform to the coding standard, too.

* Description of foo="" was completed.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

configure

@@ -169,15 +169,17 @@ case "$cpu" in
   ;;
 esac
 
-# Default value for a variable defining feature "foo"
-#  * foo="no", feature will only be used if --enable-foo arg is given
-#  * foo="", feature will be searched for, and if found, will be used
-#  * foo="yes", this value vill only be set by --enable-foo flag.
-#                   feature will searched for, if not found, configure exits with error
+# Default value for a variable defining feature "foo".
+#  * foo="no"  feature will only be used if --enable-foo arg is given
+#  * foo=""    feature will be searched for, and if found, will be used
+#              unless --disable-foo is given
+#  * foo="yes" this value will only be set by --enable-foo flag.
+#              feature will searched for,
+#              if not found, configure exits with error
 #
-# Always add --enable-foo and --disable-foo command line args.  Distributions want
-# to ensure that several features are compiled in, and it is impossible without a
-# --enable-foo that exits if feature is not found
+# Always add --enable-foo and --disable-foo command line args.
+# Distributions want to ensure that several features are compiled in, and it
+# is impossible without a --enable-foo that exits if a feature is not found.
 
 bluez=""
 brlapi=""