Better lowering of distinct types. Noreturn function call expr recognized as a "jump" for escape analysis. Preferring "def" in libs. To upper / to lower for ascii. Initial dynlib support.

lib/std/core/dstring.c3

@@ -1,6 +1,6 @@
 module std::core::dstring;
 
-typedef DString = distinct void*;
+def DString = distinct void*;
 
 const usz MIN_CAPACITY @private = 16;