Bug 2910691: Duplicate build options

CHANGES.txt

@@ -9,6 +9,7 @@
 - Added os.executef()
 - Bug 2909463: Fix Xcode handling of Obj-C++ .mm files
 - Bug 2903430: Using relative instead of absolute paths with $() macro
+- Bug 2910691: Duplicate build options
 
 
 -------

src/base/configs.lua

@@ -158,7 +158,15 @@
 		for field, value in pairs(src) do
 			if not nocopy[field] then
 				if type(value) == "table" then
-					dest[field] = table.join(dest[field] or {}, value)
+					-- merge two lists, removing any duplicates along the way
+					local tbl = dest[field] or { }
+					for _, item in ipairs(value) do
+						if not tbl[item] then
+							table.insert(tbl, item)
+							tbl[item] = item
+						end
+					end
+					dest[field] = tbl
 				else
 					dest[field] = value
 				end