build: request c++ compiler for host and build machine

meson complains:

../meson.build:34: WARNING: add_languages is missing native:, assuming languages are wanted for both host and build.

The ci builds are using cross compiler, thus we need the c++ compiler in
this scenario.

Signed-off-by: Daniel Wagner <wagi@kernel.org>

Author: igaw

meson.build

@@ -31,7 +31,7 @@ endif
 
 ################################################################################
 cc = meson.get_compiler('c')
-cxx_available = add_languages('cpp', required: false)
+cxx_available = add_languages('cpp', required: false, native: false)
 
 prefixdir  = get_option('prefix')
 libdir     = join_paths(prefixdir, get_option('libdir'))