unit-test: add basic header validation tests

Ensure header size is correct and write tests to validate it.

The goal of this patch series is to match with the validation done
within openslp (slp_v2message.c, SLPv2MessageParseHeader)

Change-Id: I42aace162051a9e4795ebbaf36f193efe4738dcd
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/meson.options b/meson.options
new file mode 100644
index 0000000..0fc2767
--- /dev/null
+++ b/meson.options
@@ -0,0 +1 @@
+option('tests', type: 'feature', description: 'Build tests')