From 6fadd5aea234c8726b14b0097e0f9e1a5606c191 Mon Sep 17 00:00:00 2001
From: ZmnSCPxj jxPCSnmZ <zmnscpxj@protonmail.com>
Date: Wed, 5 Aug 2020 22:26:16 +0800
Subject: [PATCH] Makefile: Remove gen_version.h from ALL_GEN_HEADERS.

This prevents recompiling everything when you are changing just a doc, or
touching only one file among hundreds of sources, just because the
`gen_version.h` is changed, especially since only one source actually
depends on that header.
---
 Makefile         | 2 --
 common/Makefile  | 3 +++
 common/version.c | 4 +++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index a396fbf5f..b5a3eda67 100644
--- a/Makefile
+++ b/Makefile
@@ -196,8 +196,6 @@ CCAN_HEADERS :=						\
 	$(CCANDIR)/ccan/typesafe_cb/typesafe_cb.h	\
 	$(CCANDIR)/ccan/utf8/utf8.h
 
-ALL_GEN_HEADERS += gen_version.h
-
 CDUMP_OBJS := ccan-cdump.o ccan-strmap.o
 
 BOLT_GEN := tools/generate-wire.py
diff --git a/common/Makefile b/common/Makefile
index bcce39002..c56be7466 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -96,6 +96,9 @@ COMMON_OBJS := $(COMMON_SRC:.c=.o)
 # Common objects depends on bitcoin/ external/ and ccan
 $(COMMON_OBJS): $(CCAN_HEADERS) $(BITCOIN_HEADERS) $(EXTERNAL_HEADERS) $(COMMON_HEADERS_GEN)
 
+# Only common/version.c can include this header.
+common/version.o: gen_version.h
+
 ALL_GEN_HEADERS += $(COMMON_HEADERS_GEN)
 ALL_OBJS += $(COMMON_OBJS)
 
diff --git a/common/version.c b/common/version.c
index 0bc7772ef..ea6aef255 100644
--- a/common/version.c
+++ b/common/version.c
@@ -1,7 +1,9 @@
-#include "gen_version.h"
 #include "version.h"
 #include <stdio.h>
 
+/* Only common/version.c can safely include this.  */
+# include "gen_version.h"
+
 const char *version(void)
 {
 	return VERSION;