From 814a73227f9571d8fbd831fedced5e87cd9c926b Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 9 Jan 2014 16:54:01 +0100
Subject: [PATCH] Remove duplicate elements from *_SOURCES

This is useful when you do:

  foo_SOURCES := $(wildcard *.cc) foo.cc

where foo.cc is a generated file.  In this case, if foo.cc already
exists, you get foo.cc twice in foo_SOURCES, leading to a link error.
---
 libraries.mk | 2 +-
 programs.mk  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libraries.mk b/libraries.mk
index bc258b799..98cc9f363 100644
--- a/libraries.mk
+++ b/libraries.mk
@@ -35,7 +35,7 @@ libs_list :=
 define build-library =
   $(1)_NAME ?= $(1)
   _d := $$(strip $$($(1)_DIR))
-  _srcs := $$(foreach src, $$($(1)_SOURCES), $$(src))
+  _srcs := $$(sort $$(foreach src, $$($(1)_SOURCES), $$(src)))
   $(1)_OBJS := $$(addsuffix .o, $$(basename $$(_srcs)))
   _libs := $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_PATH))
 
diff --git a/programs.mk b/programs.mk
index 52e55598c..a97a51635 100644
--- a/programs.mk
+++ b/programs.mk
@@ -17,7 +17,7 @@ programs_list :=
 #   installed; defaults to $(bindir).
 define build-program =
   _d := $$($(1)_DIR)
-  _srcs := $$(foreach src, $$($(1)_SOURCES), $$(src))
+  _srcs := $$(sort $$(foreach src, $$($(1)_SOURCES), $$(src)))
   $(1)_OBJS := $$(addsuffix .o, $$(basename $$(_srcs)))
   _libs := $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_PATH))
   $(1)_PATH := $$(_d)/$(1)