build/core: Add 'nolog' build option to omit logging entirely

This can be used to avoid dereferencing the global `log_type`
which may be inaccessible on platforms with memory protection.

Change-Id: Ib48468018e3afaf05978018199a9a2022cb49fdf
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
diff --git a/meson.options b/meson.options
index 73c23be..fda6e56 100644
--- a/meson.options
+++ b/meson.options
@@ -37,3 +37,9 @@
     value: false,
     description: 'Use fixed application-provided allocators',
 )
+option(
+    'nolog',
+    type: 'boolean',
+    value: false,
+    description: 'Don\'t include any logging functionality',
+)