Add support for Windows

Author: odow

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         version: ['1.6', '1']  # Test against LTS and current minor release
-        os: [ubuntu-latest, macOS-latest]  # MiniZinc_jll broken on windows-latest
+        os: [ubuntu-latest, macOS-latest, windows-latest]
         arch: [x64]
     steps:
       - uses: actions/checkout@v2

README.md

@@ -26,16 +26,8 @@ import Pkg
 Pkg.add("MiniZinc")
 ```
 
-**Windows**
-
-On Linux and macOS, this package automatically installs `libminizinc`. However,
-we're still working out problems with the install on Windows. To use
-MiniZinc.jl, you'll need to manually install a copy of `libminizinc` from
-[minizinc.org](https://www.minizinc.org) or compile one yourself from
-[MiniZinc/libminizinc](https://github.com/MiniZinc/libminizinc).
-
-To teach MiniZinc.jl where to look for `libminizinc`, set the
-`JULIA_LIBMINIZINC_DIR` environment variable. For example:
+To use a custom install of MiniZinc, set the `JULIA_LIBMINIZINC_DIR` environment
+variable. For example:
 ```julia
 ENV["JULIA_LIBMINIZINC_DIR"] = "C:\\Program Files\\MiniZinc"
 ```

src/optimize.jl

@@ -45,14 +45,8 @@ function _minizinc_exe(f::F) where {F}
         else
             return f(joinpath(user_dir, "minizinc"))
         end
-    elseif Sys.islinux() || Sys.isapple()
-        return MiniZinc_jll.minizinc(f)
     end
-    return error(
-        "Unable to call libminizinc. Please manually install a copy and set " *
-        "the `JULIA_LIBMINIZINC_DIR` environment variable. See the README.md " *
-        "for more details",
-    )
+    return MiniZinc_jll.minizinc(f)
 end
 
 function _run_minizinc(dest::Optimizer)