Check that statics are sized. Closes #26

tests/compile-fail/static_is_sized.rs

@@ -0,0 +1,10 @@
+#[macro_use]
+extern crate lazy_static;
+
+lazy_static! {
+    pub static ref FOO: str = panic!();
+}
+//^ ERROR `str` does not have a constant size known at compile-time
+
+fn main() {
+}