Start using automatic git-based versioning

.gitignore

@@ -42,3 +42,7 @@ shairport-sync.core
 # macOS stuff
 .DS_Store
 shairport-sync.xcodeproj
+
+# version string generation
+gitversion.h
+

Makefile.am

@@ -32,6 +32,18 @@ else
 endif
 endif
 
+# include information generated by 'git describe --dirty' if requested
+if USE_GIT_VERSION
+common.c: gitversion.h
+gitversion.h: .git/index
+	echo "// Do not edit!" > gitversion.h
+	echo "// This file is automatically generated by 'git describe --dirty', if available." >> gitversion.h
+	echo -n "  char git_version_string[] = \"" >> gitversion.h
+	git describe --dirty | tr -d '[[:space:]]' >> gitversion.h
+	echo "\";" >> gitversion.h
+CLEANFILES += gitversion.h
+endif
+
 if USE_APPLE_ALAC
   shairport_sync_SOURCES += apple_alac.cpp
 endif

common.c

@@ -2,7 +2,7 @@
  * Utility routines. This file is part of Shairport.
  * Copyright (c) James Laird 2013
  * The volume to attenuation function vol2attn copyright (c) Mike Brady 2014
- * Further changes and additions (c) Mike Brady 2014 -- 2019
+ * Further changes and additions (c) Mike Brady 2014 -- 2021
  * All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person
@@ -27,6 +27,11 @@
  */
 
 #include "common.h"
+
+#ifdef CONFIG_USE_GIT_VERSION_STRING
+#include "gitversion.h"
+#endif
+
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -88,6 +93,8 @@
 #include <syslog.h>
 #endif
 
+
+
 #ifdef CONFIG_ALSA
 void set_alsa_out_dev(char *);
 #endif
@@ -1602,9 +1609,16 @@ void pthread_cleanup_debug_mutex_unlock(void *arg) { pthread_mutex_unlock((pthre
 
 char *get_version_string() {
   char *version_string = malloc(1024);
-  if (version_string) {
+  if (version_string) {  
+#ifdef CONFIG_USE_GIT_VERSION_STRING
+  if (git_version_string[0] != '\0') 
+    strcpy(version_string, git_version_string);
+  else
+#endif
     strcpy(version_string, PACKAGE_VERSION);
-
+#ifdef CONFIG_AIRPLAY_2
+  strcat(version_string, "-AirPlay2");
+#endif
 #ifdef CONFIG_APPLE_ALAC
     strcat(version_string, "-alac");
 #endif

configure.ac

@@ -8,6 +8,13 @@ AC_CONFIG_SRCDIR([shairport.c])
 AC_CONFIG_HEADERS([config.h])
 AC_PROG_RANLIB
 
+AC_CHECK_PROGS([GIT], [git])
+if test -n "$GIT"; then
+  AC_DEFINE([CONFIG_USE_GIT_VERSION_STRING], 1, [Use the version string produced by running 'git describe --dirty'.])
+fi
+AM_CONDITIONAL([USE_GIT_VERSION], [test -n "$GIT"])
+
+
 # Derived from the Avahi configure.ac file
 # Specifying the OS type, defaulting to linux.
 #