[Listener] print_version(): print version number

Use git describe to generate a version label. One can also specify a
label:
  make OWLPS_VERSION=v3.14alpha

owlps-listener/Makefile

@@ -1,3 +1,8 @@
+# Source version
+ifndef OWLPS_VERSION
+	OWLPS_VERSION = $$(git describe || echo 'UNKNOWN_VERSION')
+endif
+
 # Répertoire d'installation
 PREFIX=/usr/local
 INSTALL_DIR= $(PREFIX)/sbin
@@ -27,7 +32,8 @@ CFLAGS = -O2 -Wall -Wextra -Wstrict-prototypes \
 DEPFLAGS = -MMD
 XCFLAGS = $(CFLAGS) $(DEPFLAGS) $(WARN) $(HEADERS)
 PICFLAG = -fPIC
-OWLPSFLAGS = -D USE_CONFIG_FILE -lconfuse -D USE_PTHREAD -pthread
+OWLPSFLAGS = -D OWLPS_VERSION=\"$(OWLPS_VERSION)\" \
+	-D USE_CONFIG_FILE -lconfuse -D USE_PTHREAD -pthread
 LIBS = -L$(LIBOWLPS_DIR) -lowlps \
 	-L$(LIBOWLPSCLIENT_DIR) -lowlps-client \
 	-lpcap

owlps-listener/Makefile_atheros

@@ -1,3 +1,8 @@
+# Source version
+ifndef OWLPS_VERSION
+	OWLPS_VERSION = $$(git describe)
+endif
+
 # Emplacement de la suite de cross-compilation
 TOOLCHAIN_PREFIX = $$HOME/openwrt/atheros/8.09
 TOOLCHAIN_BIN = $(TOOLCHAIN_PREFIX)/staging_dir/toolchain-mips_gcc4.1.2/bin
@@ -36,7 +41,8 @@ LOWLPSCLIENTA = $(LIBOWLPSCLIENT_DIR)/libowlps-client.a
 LIBS = -lpcap -liw -lm $(LOWLPSCLIENTA)
 LATHEROS = -L$(TOOLCHAIN_USR)/lib -L$(TOOLCHAIN_USR_2)/lib
 IATHEROS = -I$(TOOLCHAIN_USR)/include -I$(TOOLCHAIN_USR_2)/include
-OWLPSFLAGS = -D USE_PTHREAD -pthread
+OWLPSFLAGS = -D OWLPS_VERSION=\"$(OWLPS_VERSION)\" \
+	-D USE_PTHREAD -pthread
 #OWLPSFLAGS += -D USE_CONFIG_FILE -lconfuse
 LDFLAGS = $(OWLPSFLAGS) $(LIBS)
 

owlps-listener/owlps-listenerd.c

@@ -1346,7 +1346,7 @@ void print_usage()
 
          "Main options:\n"
          "\t-h\t\tPrint this help.\n"
-         "\t-V\t\tShow version.\n"
+         "\t-V\t\tShow version information.\n"
          "\t-f config_file\tUse 'config_file' instead of the default"
          " configuration file (%s). Available only if program was"
          " compiled with libconfuse.\n"
@@ -1411,12 +1411,18 @@ void print_usage()
 
 void print_version()
 {
-  printf("This is OWLPS Listener, part of the Open Wireless Positioning"
+  printf("This is OwlPS Listener, part of the Open Wireless Positioning"
          " System project.\n"
-         "\n"
+         "Version: %s.\n"
          "Compilation-time options:\n"
          "\tSupport for POSIX threads: %s.\n"
          "\tSupport for configuration file (libconfuse): %s.\n",
+#ifdef OWLPS_VERSION
+         OWLPS_VERSION
+#else // OWLPS_VERSION
+         "unknown version"
+#endif // OWLPS_VERSION
+         ,
 #ifdef USE_PTHREAD
          "YES"
 #else // USE_PTHREAD