Fix for removal of limit_output

This does something useful only for multiple versions of julia-0.5, since `limit_output(io)` was introduced (+1936) and then removed (+4305). Prior to that, you couldn't call `limit_output` on an `io` object.
For earlier julia versions, this just evaluates as `false`.

For, e.g., BenchmarkTools, it seems important to be able to support a range of julia-0.5 versions.

src/Compat.jl

@@ -357,6 +357,26 @@ function rewrite_pairs_to_tuples!(expr::Expr)
     return expr
 end
 
+# rewrites accesses to IOContext dicts
+function rewrite_iocontext!(expr::Expr)
+    if expr.head == :call && expr.args[1] == :get
+        key = expr.args[3]
+        if     (((isa(key, QuoteNode) && key.value == :limit) ||
+                 (isa(key, Expr) && key.head == :quote && key.args[1] == :limit))
+                && expr.args[4] == false)
+            if VERSION >= v"0.5.0-dev+1936" && VERSION < v"0.5.0-dev+4305"
+                expr.args[1] = :(Base.limit_output)
+                deleteat!(expr.args, 3:4)
+            elseif VERSION < v"0.5.0-dev+1936"
+                expr.head = :quote
+                expr.args[1] = false
+                deleteat!(expr.args, 3:4)
+            end
+        end
+    end
+    expr
+end
+
 if VERSION < v"0.4.0-dev+707"
     macro inline(ex)
         esc(ex)
@@ -515,6 +535,9 @@ function _compat(ex::Expr)
         elseif VERSION < v"0.4.0-dev+1246" && f == :String
             ex = Expr(:call, :bytestring, ex.args[2:end]...)
         end
+        if VERSION < v"0.5.0-dev+4305"
+            rewrite_iocontext!(ex)
+        end
     elseif ex.head === :curly
         f = ex.args[1]
         if VERSION < v"0.4.0-dev+4319" && f === :Tuple

test/runtests.jl

@@ -1183,3 +1183,6 @@ if VERSION < v"0.5.0-dev+4267"
 else
     @test Compat.KERNEL == Sys.KERNEL
 end
+
+io = IOBuffer()
+@test @compat(get(io, :limit, false)) == false