Implemented mapping of MSVC to VS 2017 in build scripts.

build/scripts/LLVM.lua

@@ -47,19 +47,19 @@ function clone_llvm()
   git.reset_hard(llvm, llvm_release)
   git.reset_hard(clang, clang_release)
 end
-
 function get_vs_version()
-  local function map_msvc_to_vs_version(ver)
-    if     ver == "19" then return "vs2015"
-    elseif ver == "18" then return "vs2013"
-    elseif ver == "17" then return "vs2012"
+  local function map_msvc_to_vs_version(major, minor)
+    if major == "19" and minor == "10" then return "vs2017"
+    elseif major == "19" then return "vs2015"
+    elseif major == "18" then return "vs2013"
+    elseif major == "17" then return "vs2012"
     else error("Unknown MSVC compiler version, run in VS command prompt.") end
   end
 
   local out = outputof("cl")
-  local ver, arch = string.match(out, '(%d+).%d+.%d+.?%d*%s+')
-
-  return map_msvc_to_vs_version(ver)
+  local major, minor = string.match(out, '(%d+).(%d+).%d+.?%d*%s+')
+  
+  return map_msvc_to_vs_version(major, minor)
 end
 
 function get_toolset_configuration_name()