Merge branch 'refs/heads/t/makefile_conventions'

A bunch of changes which strive to make the paraslash build system
more standard.

Cooking for three months.

* refs/heads/t/makefile_conventions:
  build: Add target "check" as a synonym for "test".
  build: Rename target "tarball" to "dist".
  build: Do not strip installed executables by default.
  build: Support $(DESTDIR).
  build: Rename clean targets.

diff --cc Makefile.in
Simple merge

diff --cc Makefile.real
Simple merge

diff --cc NEWS.md
index 6184335efc75d61deec713ca43d559ce9b2f0a24,d9326db76cfa80b50a8a268fef1b29f966cdeb09..ae0c14b5d57c72e046e13d7fd0c129adf6fe46fb
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -1,26 -1,6 +1,34 @@@
  NEWS
  ====
  
 +------------------------------------
 +0.6.0 (to be announced) "fuzzy flux"
 +------------------------------------
 +- Support for Mac OS X has been removed.
 +- On Linux systems, glibc-2.17 or newer is required to build the
 +  source tree.
 +- Support for RSA public keys in ASN format (as generated by openssl
 +  genrsa) has been removed. These keys have been deprecated since
 +  2011, so users should have long switched to keys generated with
 +  ssh-keygen(1).
 +- If libgcrypt is used as the crypto library, we now require version
 +  1.5.0 (released in 2011) or later.
 +- The insecure RC4 stream cipher has been removed. It was superseded
 +  by aes_ctr128 three years ago but the RC4 code had been kept for
 +  backwards compatibility.
 +- On Linux, abstract unix domain sockets are used unconditionally.
++- The "install" target no longer strips executables, the new
++  install-strip target can be used to get the old behaviour.
++- The clean targets have been renamed: clean2 is gone, and the new
++  mostlyclean removes only the executables and object files.
++- New target: check (identical to test).
++- The DESTDIR make variable is honored to prepend a path to the
++  installation directory. This feature is orthogonal to the --prefix
++  option to configure.
 +
 +Downloads:
 +[tarball](./releases/paraslash-git.tar.bz2),
 +
  -------------------------------------
  0.5.7 (2016-12-31) "semantic density"
  -------------------------------------

diff --cc configure.ac
Simple merge