Reset GNUMAKEFLAGS after parsing.

If we don't do this we'll continually add flags on recursion.  This
is mainly for users to set in their environment before invoking make.

1 files changed, 11 insertions, 4 deletions

diff --git a/doc/make.texi b/doc/make.texi
index f89f8b7..42cec7f 100644
--- a/doc/make.texi
+++ b/doc/make.texi
@@ -4808,10 +4808,17 @@ to GNU @code{make}, and hence do not want to add GNU
 @code{make}-specific flags to the @code{MAKEFLAGS} variable, you can
 add them to the @code{GNUMAKEFLAGS} variable instead.  This variable
 is parsed just before @code{MAKEFLAGS}, in the same way as
-@code{MAKEFLAGS}.  Note, however, that when @code{make} constructs
-@code{MAKEFLAGS} to pass to a recursive @code{make} it will include
-all flags.  GNU @code{make} never sets the @code{GNUMAKEFLAGS}
-variable itself.
+@code{MAKEFLAGS}.  When @code{make} constructs @code{MAKEFLAGS} to
+pass to a recursive @code{make} it will include all flags, even those
+taken from @code{GNUMAKEFLAGS}.  As a result, after parsing
+@code{GNUMAKEFLAGS} GNU @code{make} sets this variable to the empty
+string to avoid duplicating flags during recursion.
+
+It's best to use @code{GNUMAKEFLAGS} only with flags which won't
+materially change the behavior of your makefiles.  If your makefiles
+require GNU make anyway then simply use @code{MAKEFLAGS}.  Flags such
+as @samp{--no-print-directory} or @samp{--output-sync} may be
+appropriate for @code{GNUMAKEFLAGS}.
 
 @node -w Option,  , Options/Recursion, Recursion
 @subsection The @samp{--print-directory} Option