Merge topic branch t/build into master

A medium sized series for the build system which improves the way the git
version string is stored in the executables and man pages. Subsequent patches
of the series remove some warts from the makefile: we no longer use order-only
dependencies and the .PRECIOUS target.

The merge results in a conflict against the "remove regex include" commit
67388cd4fae0. This is trivial to resolve, though.

* refs/heads/t/build:
  Doxify version functions.
  Doxify OV_EXCLUDE_STATIC_CALLBACKS #define.
  Makefile: Fix braino in tarball target.
  build: Remove superfluous dependency in Makefile.real.
  build: Remove the .PRECIOUS target.
  build: Improve clean targets.
  build: Get rid of directory order-only dependencies.
  build: Compile with -Wunused -Wall also on BSD.
  build: Revamp git versioning.
  build: Merge version.{c,h} into string.{c,h}.

diff --cc NEWS.md
index 1ed27260e61f39c74b4f41f305755d8a9d0cd9d2,1ed27260e61f39c74b4f41f305755d8a9d0cd9d2..daec9b6a8900819c7fad20116d3ef9fca0d7aacc
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -2,9 -2,9 +2,12 @@@ NEW
  ====
  
  ------------------------------------------
--?.?.? (to be announced) "pulsating plasma"
++0.7.5 (to be announced) "pulsating plasma"
  ------------------------------------------
  
++- A bunch of build system improvements and cleanups.
++
++
  [tarball](./releases/paraslash-git.tar.xz)
  
  ----------------------------------------

diff --cc afh.c
Simple merge

diff --cc audioc.c
Simple merge

diff --cc audiod.c
Simple merge

diff --cc audiod_command.c
Simple merge

diff --cc client.c
Simple merge

diff --cc client_common.c
Simple merge

diff --cc command.c
Simple merge

diff --cc filter.c
Simple merge

diff --cc gui.c
Simple merge

diff --cc mixer.c
Simple merge

diff --cc oggdec_filter.c
index e7f0f370252ed4f36a8b11c00a082fbb919fbb69,7d9feda98f03d113dbe50603c3ea5e803630320b..c0a13af972c3bd3b45df35a15ff2c5d3d3690444
--- 1/oggdec_filter.c
--- 2/oggdec_filter.c
+++ b/oggdec_filter.c
@@@ -2,6 -2,17 +2,17 @@@
  
  /** \file oggdec_filter.c Paraslash's ogg vorbis decoder. */
  
 -#include <regex.h>
+ 
+ /**
+  * Avoid warnings on NetBSD.
+  *
+  * The static ogg-vorbis callback structures are only needed on Windows. At
+  * least with vorbistools-1.3.7, they cause warnings on NetBSD-10.0. The define
+  * below instructs the preprocessor to not define these structures, avoiding
+  * the warnings. See the comment in vorbisfile.h for details.
+  */
+ #define OV_EXCLUDE_STATIC_CALLBACKS
++
  #include <vorbis/vorbisfile.h>
  
  #include "para.h"

diff --cc play.c
Simple merge

diff --cc recv.c
Simple merge

diff --cc server.c
Simple merge

diff --cc string.c
Simple merge

diff --cc upgrade_db.c
Simple merge

diff --cc write.c
Simple merge