Document NO_SILENT for META_MODE.

Reword and add some formatting as well.

1 files changed, 15 insertions, 4 deletions

diff --git a/tools/build/options/WITH_META_MODE b/tools/build/options/WITH_META_MODE
index 16e79ae1c511..b255777956bc 100644
--- a/tools/build/options/WITH_META_MODE
+++ b/tools/build/options/WITH_META_MODE
@@ -1,11 +1,17 @@
 .\" $FreeBSD$
 Enable building in meta mode.
 .Pp
-The build is driven by dirdeps.mk using DIRDEPS stored in
+The build is driven by dirdeps.mk using
+.Va DIRDEPS
+stored in
 Makefile.depend files found in each directory.
 .Pp
 The build can be started from anywhere, and behaves the same.
-The initial instance of make recursively reads DIRDEPS from Makefile.depend
+The initial instance of
+.Xr make 1 
+recursively reads
+.Va DIRDEPS
+from Makefile.depend
 computing a graph of tree dependencies from the current origin.
 See http://www.crufty.net/help/sjg/dirdeps.htm
 .Pp
@@ -16,5 +22,10 @@ the command line,
 as well as any command output.
 If
 .Xr filemon 4
-is available the meta file will also capture a record of syscalls
-used to produce the target.
+is available the meta file will also capture a record of files
+used to produce the target by tracking syscalls.
+.Pp
+The build will hide commands ran unless
+.Va NO_SILENT
+is defined.
+.Pp