reorganize configure.in and add default values for all switches

configure.in

@@ -9,13 +9,13 @@ AC_LANG_CPLUSPLUS
 AC_PROG_CXX
 AM_PROG_LIBTOOL
 
-AC_ARG_ENABLE(clock, AS_HELP_STRING([--enable-clock], [Enable clock screen]), [clock=$enableval], [clock=no])
-AC_ARG_ENABLE(unicode, AS_HELP_STRING([--enable-unicode], [Enable utf8 support]), [unicode=$enableval], [unicode=yes])
-AC_ARG_WITH(taglib, AS_HELP_STRING([--with-taglib], [Enable tag editor]), [taglib=$withval], [taglib=auto])
-AC_ARG_WITH(pthreads, AS_HELP_STRING([--with-pthreads], [Enable threading support using posix threads]), [pthreads=$withval], [pthreads=auto])
-AC_ARG_WITH(iconv, AS_HELP_STRING([--with-iconv], [Enable iconv support (Note: if you use utf-8 system wide, you can disable this)]), [iconv=$withval], [iconv=auto])
-AC_ARG_WITH(curl, AS_HELP_STRING([--with-curl], [Enable fetching lyrics from the Internet]), [curl=$withval], [curl=auto])
+AC_ARG_ENABLE(clock, AS_HELP_STRING([--enable-clock], [Enable clock screen @<:@default=no@:>@]), [clock=$enableval], [clock=no])
+AC_ARG_ENABLE(unicode, AS_HELP_STRING([--enable-unicode], [Enable utf8 support @<:@default=yes@:>@]), [unicode=$enableval], [unicode=yes])
+AC_ARG_WITH(curl, AS_HELP_STRING([--with-curl], [Enable fetching lyrics from the Internet @<:@default=auto@:>@]), [curl=$withval], [curl=auto])
+AC_ARG_WITH(iconv, AS_HELP_STRING([--with-iconv], [Enable iconv support (Note: if you use utf-8 system wide, you can disable this) @<:@default=auto@:>@]), [iconv=$withval], [iconv=auto])
 AC_ARG_WITH(pdcurses, AS_HELP_STRING([--with-pdcurses[=LIBNAME]], [Link against pdcurses instead of ncurses @<:@default=XCurses@:>@]), [pdcurses=$withval], [pdcurses=no])
+AC_ARG_WITH(pthreads, AS_HELP_STRING([--with-pthreads], [Enable threading support using posix threads @<:@default=auto@:>@]), [pthreads=$withval], [pthreads=auto])
+AC_ARG_WITH(taglib, AS_HELP_STRING([--with-taglib], [Enable tag editor @<:@default=auto@:>@]), [taglib=$withval], [taglib=auto])
 
 if test "$clock" = "yes"; then
 	AC_DEFINE([ENABLE_CLOCK], [1], [enables clock screen])