Replace "( : ${var?} )" syntax with better "[ ${var+set} ]" syntax.

Reviewed by:	jilles, adrian (co-mentor)
Approved by:	jilles, adrian (co-mentor)

usr.sbin/bsdconfig/share/sysrc.subr

@@ -132,7 +132,7 @@ f_sysrc_get()
 		# Clear the environment of all variables, preventing the
 		# expansion of normals such as `PS1', `TERM', etc.
 		#
-		f_clean_env --except RC_CONFS RC_DEFAULTS SUCCESS
+		f_clean_env --except RC_CONFS RC_DEFAULTS
 
 		. "$RC_DEFAULTS" > /dev/null 2>&1
 
@@ -153,15 +153,11 @@ f_sysrc_get()
 		# If RC_CONFS is defined, set $rc_conf_files to an explicit
 		# value, modifying the default behavior of source_rc_confs().
 		#
-		( : ${RC_CONFS?} ) > /dev/null 2>&1
-		if [ $? -eq ${SUCCESS:-0} ]; then
+		if [ "${RC_CONFS+set}" ]; then
 			rc_conf_files="$RC_CONFS"
 			_rc_confs_set=1
 		fi
 
-		unset SUCCESS
-			# no longer needed
-
 		source_rc_confs > /dev/null 2>&1
 
 		#

usr.sbin/bsdconfig/startup/rcadd

@@ -46,7 +46,7 @@ ipgm=$( f_index_menu_selection $BSDCFG_LIBE/$APP_DIR/INDEX "$pgm" )
 # Options
 #
 # Inherit SHOW_DESC value if set, otherwise default to 1
-( : ${SHOW_DESC?} ) > /dev/null 2>&1 || SHOW_DESC=1
+[ "${SHOW_DESC+set}" ] || SHOW_DESC=1
 
 ############################################################ FUNCTIONS
 

usr.sbin/bsdconfig/startup/rcconf

@@ -54,7 +54,7 @@ RCCONF_MENU_LIST=
 # Options
 #
 # Inherit SHOW_DESC value if set, otherwise default to 1
-( : ${SHOW_DESC?} ) > /dev/null 2>&1 || SHOW_DESC=1
+[ "${SHOW_DESC+set}" ] || SHOW_DESC=1
 # Selectively inherit SHOW_* value (in order of preference)
 if [ "$SHOW_DEFAULT_VALUE" ]; then
 	SHOW_DEFAULT_VALUE=1

usr.sbin/bsdconfig/startup/rcdelete

@@ -54,7 +54,7 @@ RCCONF_MENU_LIST=
 # Options
 #
 # Inherit SHOW_DESC value if set, otherwise default to 1
-( : ${SHOW_DESC?} ) > /dev/null 2>&1 || SHOW_DESC=1
+[ "${SHOW_DESC+set}" ] || SHOW_DESC=1
 # Selectively inherit SHOW_* value (in order of preference)
 if [ "$SHOW_DEFAULT_VALUE" ]; then
 	SHOW_DEFAULT_VALUE=1
@@ -348,7 +348,7 @@ while :; do
 		var="${mtag# }"
 
 		# Toggle the state-variable and loop back to menu
-		if ( eval : \${_${var}_delete?} ) > /dev/null 2>&1; then
+		if eval [ \"\${_${var}_delete+set}\" ]; then
 			unset _${var}_delete
 		else
 			setvar _${var}_delete 1

usr.sbin/bsdconfig/startup/rcvar

@@ -54,7 +54,7 @@ RCVAR_MENU_LIST=
 # Options
 #
 # Inherit SHOW_DESC value if set, otherwise default to 1
-( ${SHOW_DESC?} ) > /dev/null 2>&1 || SHOW_DESC=1
+[ "${SHOW_DESC+set}" ] || SHOW_DESC=1
 
 ############################################################ FUNCTIONS