support weak frameworks

_preload.lua

@@ -23,6 +23,11 @@
 		kind = "list",
 	}
 
+	p.api.register {
+		name = "xcodeweakframeworks",
+		scope = "config",
+		kind = "list",
+	}
 
 --
 -- Register the Xcode exporters.

xcode_common.lua

@@ -370,8 +370,13 @@
 			onnode = function(node)
 				if node.buildid then
 					settings[node.buildid] = function(level)
-						_p(level,'%s /* %s in %s */ = {isa = PBXBuildFile; fileRef = %s /* %s */; };',
-							node.buildid, node.name, xcode.getbuildcategory(node), node.id, node.name)
+						if node.isWeak then
+							_p(level,'%s /* %s in %s */ = {isa = PBXBuildFile; fileRef = %s /* %s */;  settings = {ATTRIBUTES = (Weak, ); }; };',
+								node.buildid, node.name, xcode.getbuildcategory(node), node.id, node.name)
+						else
+							_p(level,'%s /* %s in %s */ = {isa = PBXBuildFile; fileRef = %s /* %s */; };',
+								node.buildid, node.name, xcode.getbuildcategory(node), node.id, node.name)
+						end
 					end
 				end
 			end

xcode_project.lua

@@ -73,6 +73,7 @@
 				if xcode.isframework(name) and not tr.frameworks.children[name] then
 					node = tree.insert(tr.frameworks, tree.new(name))
 					node.path = link
+					node.isWeak = (cfg.xcodeweakframeworks or {})[name]
 		 		end
 		 	end
 		 end