Add alloc feature across workspace crates

x/Cargo.toml

@@ -9,6 +9,7 @@ core = ["sub_core"]
 macros = ["sub_macros"]
 libm = ["sub_libm"]
 pe = ["sub_pe"]
+alloc = ["sub_core?/alloc", "sub_pe?/alloc", "sub_xpat?/alloc", "sub_winu?/alloc"]
 
 xpat = ["core", "sub_xpat", "macros"]
 winuser = ["sub_winu", "pe", "sub_pe/windows"]