Use a nicer version string

Dependencies

• [2] C7CXMZ66 hydra: do not perform git clone every time. in stead work on local clone and pull
• [3] V2ALOFRR Fix the test
• [4] WYM574OI add nix to buildinputs
• [5] 6NWLMLSS remove nix from buildinputs
• [6] VM3TQZ65 * hydra: make manual.pdf
• [7] 7C6HSXUQ * Start of a regression test for Hydra.
• [8] UHMUHQMU hydra: fix tarball build, add pre suffix to tarballs
• [9] M3A5PZIH hydra: Clarify the dependency on BDW-GC.
• [10] T4LLYESZ * Nix expression for building Hydra.
• [11] YQWH4POV * Simplify.

Change contents

• replacement in release.nix at line 2
  [2.31]→[4.0:42](∅→∅),[4.23]→[4.0:42](∅→∅)
  − , hydraSrc ? {outPath = ./.; rev = 1234;}
  [2.31]

  [4.65]
  + , hydraSrc ? { outPath = ./.; revCount = 1234; gitTag = "abcdef"; }
• replacement in release.nix at line 20
  [4.60]→[3.0:73](∅→∅)
  − [ perl libxslt dblatex tetex nukeReferences pkgconfig boehmgc ];
  [4.60]

  [4.76]
  + [ perl libxslt dblatex tetex nukeReferences pkgconfig boehmgc git ];
• edit in release.nix at line 22
  [4.77]

  [4.77]
  + versionSuffix = if officialRelease then "" else "pre${toString hydraSrc.revCount}-${hydraSrc.gitTag}";

  +