[cmake][addons] allow passing extra args to built addon dependencies

Allows a user to pass through cmake arguments to all addon dependencies that are built
Be aware, this is a global addition, and will be passed through to all addons built.

Usage:

-DADDON_EXTRA_ARGS="-Ddefine1=1 -Ddefine2=2"

The arguments will be passed through as a list (ie -Ddefine1=1;-Ddefine2=2) to all
addon dependencies built, and will be accessible via their CMakelists.txt files

an example is with visualization.projectm. If a user wishes to set -DAPP_RENDER_SYSTEM=gles
for the projectm dependency to build projectm as gles compatible.

Currently this can be done with a toolchain file, but a user cant set -DAPP_RENDER_SYSTEM=gles
as art of their cmake stanza to build the addon, as dependencies are passed through filtered
lists, of which APP_RENDER_SYSTEM isnt specifically passed through.

https://github.com/xbmc/visualization.projectm/issues/87

This solution provides a more generic way to pass through arguments to cmake dependencies
without us explicitly handling each option in HandleDepends.cmake

1 files changed, 2 insertions, 0 deletions

diff --git a/cmake/addons/depends/README b/cmake/addons/depends/README
index 6e62a20fb0..76df28454e 100644
--- a/cmake/addons/depends/README
+++ b/cmake/addons/depends/README
@@ -31,3 +31,5 @@ into it when executing cmake with the -D<variable-name>=<value> option) to e.g.
 access specific paths:
   * DEPENDS_TO_BUILD is a quoted, space delimited list of <dependency>s that
     you want to build (default is "all").
+  * ADDON_EXTRA_ARGS is a quoted, space delimited list of arguments passed to
+    all <dependency>s built (eg -DADDON_EXTRA_ARGS="-Darg1=1 -Darg2=2").