Fail gracefully when list is assigned to string field

CHANGES.txt

@@ -4,6 +4,7 @@
 
 - Bug 2564404: FatalWarnings has no effect with gmake target
 - Support links and libdirs for Visual Studio static libraries
+- Fail gracefully when list is assigned to string field
 
 
 -----

src/base/api.lua

@@ -457,11 +457,17 @@
 -- The getter/setter implemention.
 --
 
-	local function accessor(name, value)
+	local function accessor(name, value)		
 		local kind    = premake.fields[name].kind
 		local scope   = premake.fields[name].scope
 		local allowed = premake.fields[name].allowed
 		
+		if (kind == "string" or kind == "path" and value) then
+			if type(value) ~= "string" then
+				error("string value expected", 3)
+			end
+		end
+		
 		if (kind == "string") then
 			return premake.setstring(scope, name, value, allowed)
 		elseif (kind == "path") then