util: introduce common version() implementation and use it everywhere

This also allows us to drop build.h from a ton of files, hence do so.
Since we touched the #includes of those files, let's order them properly
according to CODING_STYLE.

src/basic/util.c

@@ -72,6 +72,7 @@
  * otherwise conflicts with sys/mount.h. Yay, Linux is great! */
 #include <linux/fs.h>
 
+#include "build.h"
 #include "def.h"
 #include "device-nodes.h"
 #include "env-util.h"
@@ -6920,3 +6921,9 @@ int receive_one_fd(int transport_fd, int flags) {
 void nop_signal_handler(int sig) {
         /* nothing here */
 }
+
+int version(void) {
+        puts(PACKAGE_STRING "\n"
+             SYSTEMD_FEATURES);
+        return 0;
+}

src/basic/util.h

@@ -946,3 +946,5 @@ int send_one_fd(int transport_fd, int fd, int flags);
 int receive_one_fd(int transport_fd, int flags);
 
 void nop_signal_handler(int sig);
+
+int version(void);