pkg-cmake: allow to build package in a subdirectory

For some cmake based packages, like GNURadio, it's forbidden to do the
compilation directly in the sources directory. This patch add a new
variable to specify, if needed, the name of a sub-directory used to compile.

[Thomas: put the documentation at the right place in the manual, not
in the middle of the <pkg>_CONF_OPTS description.]

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Tested-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/docs/manual/adding-packages-cmake.txt b/docs/manual/adding-packages-cmake.txt
index d92b2090f8..6ccf3902f8 100644
--- a/docs/manual/adding-packages-cmake.txt
+++ b/docs/manual/adding-packages-cmake.txt
@@ -107,6 +107,10 @@ typical packages will therefore only use a few of them.
 ** +BUILD_EXAMPLE+, +BUILD_EXAMPLES+ are disabled;
 ** +BUILD_TEST+, +BUILD_TESTS+, +BUILD_TESTING+ are disabled.
 
+* +LIBFOO_SUPPORTS_IN_SOURCE_BUILD = NO+ should be set when the package
+  cannot be built inside the source tree but needs a separate build
+  directory.
+
 * +LIBFOO_MAKE+, to specify an alternate +make+ command. This is
   typically useful when parallel make is enabled in the configuration
   (using +BR2_JLEVEL+) but that this feature should be disabled for