Refactor vars handling when adding C/C++ build rules.

Author: tritao

ninja.lua

@@ -565,19 +565,21 @@ local function compile_file_build(cfg, filecfg, toolset, pch_dependency, regular
 	elseif shouldcompileasc(filecfg) then
 		local objfilename = obj_dir .. "/" .. filecfg.objname .. (toolset.objectextension or ".o")
 		objfiles[#objfiles + 1] = objfilename
-		local cflags = {}
+		local vars = {}
 		if has_custom_settings then
-			cflags = {"CFLAGS = $CFLAGS " .. getcflags(toolset, cfg, filecfg)}
+			cflags = "CFLAGS = $CFLAGS " .. getcflags(toolset, cfg, filecfg)
+			vars = { cflags }
 		end
-		ninja.add_build(cfg, objfilename, {}, iif(use_clangtidy, "clangtidy_cc", "cc"), {filepath}, pch_dependency, regular_file_dependencies, cflags)
+		ninja.add_build(cfg, objfilename, {}, iif(use_clangtidy, "clangtidy_cc", "cc"), {filepath}, pch_dependency, regular_file_dependencies, vars)
 	elseif shouldcompileascpp(filecfg) then
 		local objfilename = obj_dir .. "/" .. filecfg.objname .. (toolset.objectextension or ".o")
 		objfiles[#objfiles + 1] = objfilename
-		local cxxflags = {}
+		local vars = {}
 		if has_custom_settings then
-			cxxflags = {"CXXFLAGS = $CXXFLAGS " .. getcxxflags(toolset, cfg, filecfg)}
+			cxxflags = "CXXFLAGS = $CXXFLAGS " .. getcxxflags(toolset, cfg, filecfg)
+			vars = { cxxflags }
 		end
-		ninja.add_build(cfg, objfilename, {}, iif(use_clangtidy, "clangtidy_cxx", "cxx"), {filepath}, pch_dependency, regular_file_dependencies, cxxflags)
+		ninja.add_build(cfg, objfilename, {}, iif(use_clangtidy, "clangtidy_cxx", "cxx"), {filepath}, pch_dependency, regular_file_dependencies, vars)
 	elseif path.isresourcefile(filecfg.abspath) then
 		local objfilename = obj_dir .. "/" .. filecfg.basename .. ".res"
 		objfiles[#objfiles + 1] = objfilename