examples: improve error report for missing meson deps

When a required library is missing on a platform, rather than having
meson report an error about the missing variable, catch the problem
earlier and provide a more readable message.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Tested-by: Harry van Haaren <harry.van.haaren@intel.com>

diff --git a/examples/meson.build b/examples/meson.build
index 16c3ab0..3d15684 100644 (file)
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -32,8 +32,11 @@ foreach example: examples
        if build
                dep_objs = ext_deps
                foreach d:deps
-                       dep_objs += [get_variable(
-                               get_option('default_library') + '_rte_' + d)]
+                       var_name = get_option('default_library') + '_rte_' + d
+                       if not is_variable(var_name)
+                               error('Missing dependency "@0@" for example "@1@"'.format(d, name))
+                       endif
+                       dep_objs += [get_variable(var_name)]
                endforeach
                if allow_experimental_apis
                        cflags += '-DALLOW_EXPERIMENTAL_API'