Got LibSodium building on Windows

src/Cryptography.cake

@@ -3,7 +3,12 @@
 (import "CHelpers.cake" "BuildTools.cake" "Dependencies.cake")
 
 (export-and-evaluate
- (add-c-search-directory-module "cakelisp_cache/LibSodiumInstallDir/include")
+ (comptime-cond
+  ('Unix
+   (add-c-search-directory-module "cakelisp_cache/LibSodiumInstallDir/include"))
+  ('Windows
+   (c-preprocessor-define SODIUM_STATIC)
+   (add-c-search-directory-module "Dependencies/libsodium/src/libsodium/include")))
  (c-import "sodium.h"))
 
 (defun cryptography-initialize (&return bool)
@@ -51,7 +56,7 @@
 
 (defun-comptime build-libsodium (manager (& ModuleManager) module (* Module) &return bool)
   (var libsodium-archive (* (const char))
-    (comptime-cond ('Windows "Dependencies/libsodium/libsodium.lib")
+    (comptime-cond ('Windows "Dependencies/libsodium/bin/x64/Release/v141/static/libsodium.lib")
                    ('Unix "cakelisp_cache/LibSodiumInstallDir/lib/libsodium.a")))
   ;; Already built?
   ;; We could enhance this by checking for modifications, but that's pretty rare
@@ -103,7 +108,15 @@
        "failed at LibSodium make install. Was there a configuration issue with --prefix?")
       (return false)))
    ('Windows
-    (comptime-error "Need windows support for libsodium building")))
+    (run-process-sequential-or
+        ("MSBuild.exe" "libsodium.sln" "-verbosity:minimal"
+                       "/p:Configuration=StaticRelease" "/p:Platform=x64"
+                       :in-directory "Dependencies/libsodium/builds/msvc/vs2017")
+      (Log "failed to build libsodium via MSBuild. The vs2017 version was used. Edit
+ gamelib/src/Cryptography.cake if you want to use a different version. You may also need to change
+ the libsodium solution in order to use your desired platform SDK.\n")
+      (return false))
+    (return false)))
 
   ;; One final to check to ensure everything's good to go
   (unless (fileExists libsodium-archive)
@@ -114,7 +127,11 @@
   (return true))
 (add-compile-time-hook-module pre-build build-libsodium)
 
-(add-static-link-objects "cakelisp_cache/LibSodiumInstallDir/lib/libsodium.a")
+(comptime-cond
+ ('Unix
+  (add-static-link-objects "cakelisp_cache/LibSodiumInstallDir/lib/libsodium.a"))
+ ('Windows
+  (add-static-link-objects "Dependencies/libsodium/bin/x64/Release/v141/static/libsodium.lib")))
 
 (add-dependency-git-submodule
  clone-libsodium