diff --git a/.bam/functions.lua b/.bam/functions.lua
index 2012809..2a501b7 100644
--- a/.bam/functions.lua
+++ b/.bam/functions.lua
@@ -23,13 +23,12 @@ end
 -- Returns nil if system could not be determined.
 function host_system()
 
-	if family ~= nil then
-		if family == "windows" then
-			return _systems[1]
-		end
-		if family == "unix" then
-			return _systems[2]
-		end
+	-- Check "platform" variable set by bam first.
+	if platform == "win32" or platform == "win64" then
+		return _systems[1]
+	end
+	if platform == "linux" then
+		return _systems[2]
 	end
 
 	local win = os.getenv('OS')