Mac Build Fixes

+ Add "smoke test" build CI to Github Actions
+ Added a configure_mac script (requires brew)
~ caddr_t -> void* (was never a part of any UNIX standard)

scripts/configure_mac

@@ -0,0 +1,8 @@
+#!/bin/sh
+set -x
+./configure\
+    --with-tcl=$(brew --prefix tcl-tk)\
+    --with-tk=$(brew --prefix tcl-tk)\
+    --with-cairo=$(brew --prefix cairo)/include\
+    "CFLAGS=-Wno-error=implicit-function-declaration"\
+    "LDFLAGS=-L$(brew --prefix cairo)/lib"