Update README.md

Added a workaround if no mathematica instalatione exists.

Author: fremling

README.md

@@ -188,6 +188,17 @@ After creating the file `deps.jl` try loading MathLink the usual way
 ```julia
 (@v1.X) pkg> using MathLink
 ```
+If you do not have a Mathematica installation at all, the above trick still works, but then you must leave the path blank 
+```julia
+const mlib = ""
+const mker = "WolframKernel"
+```
+Loading `MathLink` then proclaims
+```julia
+julia> using MathLink
+[ Info: Precompiling MathLink [18c93696-a329-5786-9845-8443133fa0b4]
+[ Info: Pretending fake installation works
+```julia
 
 
 ## Notes