src.conf.5: Make it self-documenting that the mkopts are environment-only.

Sponsored by:	EMC / Isilon Storage Division

share/mk/sys.mk

@@ -29,6 +29,11 @@ __DEFAULT_DEPENDENT_OPTIONS= \
 	STAGING/META_MODE \
 	SYSROOT/META_MODE
 
+__ENV_ONLY_OPTIONS:= \
+	${__DEFAULT_NO_OPTIONS} \
+	${__DEFAULT_YES_OPTIONS} \
+	${__DEFAULT_DEPENDENT_OPTIONS:H}
+
 # early include for customization
 # see local.sys.mk below
 # Not included when building in fmake compatibility mode (still needed

tools/build/options/WITH_META_MODE

@@ -25,11 +25,6 @@ If
 is available the meta file will also capture a record of files
 used to produce the target by tracking syscalls.
 .Pp
-This must be set in the environment or
-.Pa /etc/src-env.conf ,
-not
-.Pa /etc/src.conf .
-.Pp
 The build will hide commands ran unless
 .Va NO_SILENT
 is defined.

tools/build/options/makeman

@@ -221,6 +221,7 @@ EOF
 	show with SRCCONF=/dev/null | sort | sed 's/$/=/' > $t/src.conf
 	show settings SRCCONF=$t/src.conf | sort > $t/config_WITH_ALL
 	show without SRCCONF=/dev/null | sort > $t/config_WITHOUT_ALL
+	env_only_options="$(${make} -V __ENV_ONLY_OPTIONS)"
 
 	show_options |
 	while read opt targets ; do
@@ -289,6 +290,17 @@ EOF
 			done
 			echo '.El'
 		fi
+
+		case " ${env_only_options} " in
+			*\ ${opt#*_}\ *)
+				echo ".Pp"
+				echo "This must be set in the environment or"
+				echo ".Pa /etc/src-env.conf ,"
+				echo "not"
+				echo ".Pa /etc/src.conf ."
+				;;
+		esac
+
 		twiddle >&2
 	done
 	cat <<EOF