Support LLVM platform toolset for MSC; Clang in Visual Studio.

src/_premake_init.lua

@@ -976,11 +976,11 @@
 		end,
 	}
 
-  api.register {
-    name = "customtoolnamespace",
-    scope = "config",
-    kind = "string",
-  }
+	api.register {
+		name = "customtoolnamespace",
+		scope = "config",
+		kind = "string",
+	}
 
 	api.register {
 		name = "undefines",

src/actions/vstudio/vs2010_vcxproj.lua

@@ -1509,7 +1509,9 @@
 	function m.platformToolset(cfg)
 		local tool, version = p.config.toolset(cfg)
 		if version then
-			version = "v" .. version
+			if tonumber(version) ~= nil then
+				version = "v" .. version
+			end
 		else
 			local action = p.action.current()
 			version = action.vstudio.platformToolset

src/base/tools.lua

@@ -33,8 +33,15 @@
 		local parts
 		if identifier:startswith("v") then
 			parts = { "msc", identifier:sub(2) }
+		elseif identifier:startswith("llvm-vs") then -- support LLVM toolset in VS
+			parts = { "msc", "LLVM-vs" .. identifier:sub(8) }
 		else
 			parts = identifier:explode("-")
+
+			-- hack to check for LLVM toolsets, which would be corrupted by the previous line
+			if parts[1] == "msc" and parts[2] == "llvm" and parts[3]:startswith("vs") then
+				parts = { parts[1], "LLVM-" .. parts[3] }
+			end
 		end
 		return p.tools[parts[1]], parts[2]
 	end

tests/actions/vstudio/vc2010/test_platform_toolset.lua

@@ -86,3 +86,27 @@
 <PlatformToolset>v100</PlatformToolset>
 		]]
 	end
+
+	function suite.canOverrideFromScript_withV()
+		toolset "v120_xp"
+		prepare()
+		test.capture [[
+<PlatformToolset>v120_xp</PlatformToolset>
+		]]
+	end
+
+	function suite.canOverrideFromScript_withV()
+		toolset "LLVM-vs2010"
+		prepare()
+		test.capture [[
+<PlatformToolset>LLVM-vs2010</PlatformToolset>
+		]]
+	end
+
+	function suite.canOverrideFromScript_withMsc()
+		toolset "msc-llvm-vs2014_xp"
+		prepare()
+		test.capture [[
+<PlatformToolset>LLVM-vs2014_xp</PlatformToolset>
+		]]
+	end