Rewrite build config file generation in Premake.

The previous version used io.output which is not needed and also badly interacts with Premake internals.

build/premake5.lua

@@ -9,14 +9,6 @@ dofile "LLVM.lua"
 
 solution "CppSharp"
 
-  buildconfig = io.open("../BuildConfig.cs", "w+")
-  io.output(buildconfig)
-  io.write("namespace CppSharp.Parser", "\n{\n    ")
-  io.write("public static class BuildConfig", "\n    {\n        ")
-  io.write("public const string Choice = \"" .. action .. "\";\n")
-  io.write("    }\n}")
-  io.close(buildconfig)
-
   configurations { "Debug", "Release" }
   platforms { target_architecture() }
 

src/Parser/premake5.lua

@@ -1,3 +1,18 @@
+local buildconfig = path.join(builddir, "BuildConfig.cs")
+
+local function GenerateBuildConfig()
+  print("Generating CppSharp build configuration file 'BuildConfig.cs'")
+
+  local file = io.open(buildconfig, "w+")
+  file:write("namespace CppSharp.Parser", "\n{\n    ")
+  file:write("public static class BuildConfig", "\n    {\n        ")
+  file:write("public const string Choice = \"" .. _ACTION .. "\";\n")
+  file:write("    }\n}")
+  file:close()
+end
+
+GenerateBuildConfig()
+
 project "CppSharp.Parser"
 
   SetupManagedProject()
@@ -6,7 +21,7 @@ project "CppSharp.Parser"
   language "C#"
   clr "Unsafe"
 
-  files { "**.cs", "../../BuildConfig.cs" }
+  files { "**.cs", buildconfig }
   vpaths { ["*"] = "*" }
 
   links