Merge pull request #2 from inobulles/feature/better-build

Build fixes and improvements

build.fl

@@ -1,5 +1,5 @@
 # Copyright (c) 2024 Aymeric Wibo
-*
+#
 # @APPLE_LICENSE_HEADER_START@
 #
 # This file contains Original Code and/or Modifications of Original Code
@@ -21,6 +21,9 @@
 
 import bob
 
+assert Platform.os() != "Darwin", "libcopyfile is already provided by the system; you should not be using this."
+assert Platform.os() == "FreeBSD", "This libcopyfile reimplementation has only been validated on FreeBSD."
+
 # C compilation.
 
 let obj = Cc([