Make it easier to add syscalls for another architecture.

Much of the per-architecture duplication can be removed, so let's do so
before we add the 64-bit architectures.

Change-Id: Ieb796503c8e5353ea38c3bab768bb9a690c9a767
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 17b6141..86b164a 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -2,7 +2,7 @@
 #
 # Each non-blank, non-comment line has the following format:
 #
-# return_type func_name[:syscall_name[:call_id]]([parameter_list]) arch_list
+# return_type func_name[:syscall_name[:socketcall_id]]([parameter_list]) arch_list
 #
 # where:
 #       arch_list ::= "all" | "custom" | arch+