From b608c594799c79c227ffbb2009c9aa39b0d68033 Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Tue, 17 Nov 2020 01:42:28 -0700
Subject: [PATCH] src: make and use a config.h file

Not every system is the same.

Automatically create a config.h file that contains
"interesting" information about a system that cannot
be determined at compile time via predefined macros.

Provide this file via a CONFIG_H macro to interested
source files that can then `#include CONFIG_H` when
it's defined.

Currently only the framework is provided.  In other
words, the config.h file is created but is always
empty and the proper CONFIG_H macro definition is
passed on to interested source files.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 src/.gitignore       | 1 +
 src/GNUmakefile      | 9 ++++++---
 src/make-config-h.sh | 4 ++++
 src/peek_packet.c    | 4 ++++
 4 files changed, 15 insertions(+), 3 deletions(-)
 create mode 100755 src/make-config-h.sh

diff --git a/src/.gitignore b/src/.gitignore
index b321c54..0cb6533 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -7,6 +7,7 @@ can_user_push
 can_user_push_http.d*
 can_user_push_http.o*
 can_user_push_http
+config.h
 getent.d*
 getent.o*
 getent
diff --git a/src/GNUmakefile b/src/GNUmakefile
index 184cc5a..1e3a69f 100644
--- a/src/GNUmakefile
+++ b/src/GNUmakefile
@@ -19,7 +19,7 @@ clean :
 	rm -rf throttle.o* throttle.d* throttle
 	rm -rf ulimit512.o* ulimit512.d* ulimit512
 	rm -rf ltsha256.o* ltsha256.d* ltsha256
-	rm -f GROUP-FILE PASSWD-FILE SOCKET-FILE
+	rm -f config.h GROUP-FILE PASSWD-FILE SOCKET-FILE
 
 install :
 
@@ -51,6 +51,9 @@ SOCKET-FILE: FORCE
 		echo "$$TRACK_SOCKET_FILE" >SOCKET-FILE; \
 	fi
 
+config.h : make-config-h.sh
+	./make-config-h.sh "$(CC)" >$@
+
 can_user_push : can_user_push.c
 	$(CC) -o $@ $(CFLAGS) $?
 
@@ -69,8 +72,8 @@ list_packs.inc : list_packs.txt
 list_packs : list_packs.c list_packs.inc
 	$(CC) -o $@ $(CFLAGS) list_packs.c
 
-peek_packet : peek_packet.c
-	$(CC) -o $@ $(CFLAGS) peek_packet.c
+peek_packet : config.h peek_packet.c
+	$(CC) -o $@ $(CFLAGS) -DCONFIG_H='"config.h"' peek_packet.c
 
 rangecgi : rangecgi.c
 	$(CC) -o $@ $(CFLAGS) rangecgi.c
diff --git a/src/make-config-h.sh b/src/make-config-h.sh
new file mode 100755
index 0000000..78fe96a
--- /dev/null
+++ b/src/make-config-h.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+set -e
+CC="$1"
+: "${CC:=cc}"
diff --git a/src/peek_packet.c b/src/peek_packet.c
index fbbb324..220e2dc 100644
--- a/src/peek_packet.c
+++ b/src/peek_packet.c
@@ -195,6 +195,10 @@ NON-NULL-BYTE = %x01-FF
 
 */
 
+#ifdef CONFIG_H
+#include CONFIG_H
+#endif
+
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-- 
2.11.4.GIT