Add threadid() and nthreads() (#240)

* Add `threadid()` and `nthreads()`

* Fix `const` in definition

* Fix condition in test

* Remove condition and modify test

* Fix bug in export

Author: ranjanan

src/Compat.jl

@@ -1078,7 +1078,9 @@ if !isdefined(Base, :Threads)
         macro threads(expr)
             return esc(expr)
         end
-        export @threads
+        threadid() = 1
+        nthreads() = 1
+        export @threads, threadid, nthreads
     end
     export Threads
 end
@@ -1281,7 +1283,7 @@ else
 end
 
 if !isdefined(Base, :view)
-    const view = slice 
+    const view = slice
 end
 
 if !isdefined(Base, :pointer_to_string)

test/runtests.jl

@@ -1147,6 +1147,9 @@ using Compat.Threads
     @test true
 end
 
+# Issue #223
+@test 1 == threadid() <= nthreads()
+
 @test @compat(Symbol("foo")) === :foo
 @test @compat(Symbol("foo", "bar")) === :foobar
 @test @compat(Symbol("a_", 2)) === :a_2