[Buildroot] [PATCH v3 2/3] doc/manual: document the waf packages may need to select host-waf

[Carlos Santos <casantos@datacom.com.br>]

Now that waf has a blind Config.in.host we can require that packages
setting <PKG>_NEEDS_EXTERNAL_WAF to YES slso select host-waf.

Signed-off-by: Carlos Santos <casantos@datacom.com.br>
---
 docs/manual/adding-packages-waf.txt | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/docs/manual/adding-packages-waf.txt b/docs/manual/adding-packages-waf.txt
index 43b557c070..f38c3a6f55 100644
--- a/docs/manual/adding-packages-waf.txt
+++ b/docs/manual/adding-packages-waf.txt
@@ -64,7 +64,10 @@ also be defined.
   Buildroot to use the bundled +waf+ executable. If set to +NO+, the
   default, then Buildroot will use the waf executable provided in the
   package source tree; if set to +YES+, then Buidlroot will download,
-  install waf as a host tool and use it to build the package.
+  install waf as a host tool and use it to build the package. Packages
+  that need the host waf tool must select +BR2_PACKAGE_HOST_WAF+ in
+  their Config.in. It is not necessary to add host-waf to
+  +LIBFOO_DEPENDENCIES+, since this is done atomatically.
 
 * +LIBFOO_WAF_OPTS+, to specify additional options to pass to the
   +waf+ script at every step of the package build process: configure,
-- 
2.20.1