Exclude ar archives from computing the checksum.

It looks like ar files change between builds, at least on Mac OS. This fixes the checksum logic to not recompile Z3 every time.

Author: dragos

project/Build.scala

@@ -116,7 +116,7 @@ object ScalaZ3Build extends Build {
     val hashFile = z3Path / ".build-hash"
     def computeHash(): String = {
       hashFiles(listAllFiles(z3Path.asFile).filter { f =>
-        !f.getName.endsWith(".pyc") && !f.isHidden && !f.getName.startsWith(".")
+        !f.getName.endsWith(".pyc") && !f.isHidden && !f.getName.startsWith(".") && !f.getName.endsWith(".a")
       })
     }