Change the arg option for -O from numeric to string.

1 files changed, 17 insertions, 15 deletions

diff --git a/doc/make.texi b/doc/make.texi
index e004984..ce8e07b 100644
--- a/doc/make.texi
+++ b/doc/make.texi
@@ -8616,26 +8616,28 @@ The data base output contains file name and line number information for
 recipe and variable definitions, so it can be a useful debugging tool
 in complex environments.
 
-@item -O
+@item -O[@var{type}]
 @cindex @code{-O}
-@itemx --output-sync
+@itemx --output-sync[=@var{type}]
 @cindex @code{--output-sync}
-@cindex output of parallel execution
-@cindex parallel execution, output of
+@cindex output during parallel execution
+@cindex parallel execution, output during
 Ensure that the complete output from each recipe is printed in one
 uninterrupted sequence.  This option is only useful when using the
 @code{--jobs} option to run multiple recipes simultaneously
-(@pxref{Parallel, ,Parallel Execution}).  Without this option output
-will be displayed as it is generated by the recipes.
-
-With no argument or the argument @samp{1}, messages from each job in
-recursive makes are grouped together. With the argument @samp{2}, the
-complete output from any recursive make is grouped together. The latter
-achieves better grouping of output from related jobs, but causes longer
-delay, since messages do not appear until the recursive make has
-completed. Therefore @samp{-O} is more useful when watching the output
-while make runs, and @samp{-O2} is better suited when running a complex
-parallel build in the background and checking its output afterwards.
+(@pxref{Parallel, ,Parallel Execution})  Without this option output
+will be displayed as it is generated by the recipes.@refill
+
+With no type or the type @samp{target}, output from each individual
+target is grouped together.  With the type @samp{make}, the output
+from an entire recursive make is grouped together.  The latter
+achieves better grouping of output from related jobs, but causes
+longer delay since messages do not appear until the entire recursive
+make has completed (this does not increase the total build time,
+though).  In general @samp{target} mode is useful when watching the
+output while make runs, and @samp{make} mode is useful when running a
+complex parallel build in the background and checking its output
+afterwards.
 
 @item -q
 @cindex @code{-q}