Rework versioning system to not depend on Subversion.

I've shifted away from using the SVN revision number as a monotonic
version identifier (replacing it in the Windows version resource with
a count of days since an arbitrary epoch), and I've removed all uses
of SVN keyword expansion (replacing them with version information
written out by Buildscr).

While I'm at it, I've done a major rewrite of the affected code which
centralises all the computation of the assorted version numbers and
strings into Buildscr, so that they're all more or less alongside each
other rather than scattered across multiple source files.

I've also retired the MD5-based manifest file system. A long time ago,
it seemed like a good idea to arrange that binaries of PuTTY would
automatically cease to identify themselves as a particular upstream
version number if any changes were made to the source code, so that if
someone made a local tweak and distributed the result then I wouldn't
get blamed for the results. Since then I've decided the whole idea is
more trouble than it's worth, so now distribution tarballs will have
version information baked in and people can just cope with that.

[originally from svn r10262]

windows/putty.iss

@@ -1,5 +1,4 @@
 ; -*- no -*-
-; $Id$
 ;
 ; -- Inno Setup installer script for PuTTY and its related tools.
 ;    Last tested with Inno Setup 5.0.8.

windows/version.rc2

@@ -6,83 +6,7 @@
  * welcome.
  */
 
-/*
- * Binary versions in Windows are major.minor.build.revision. Each
- * component is 16-bit.
- * Here we have:
- *   major.minor
- *     PuTTY version number (e.g. 0.58). (We've made a policy decision
- *     that these will be numeric from now on.)
- *     Present in releases and snapshots (for the sake of monotonicity
- *     in version numbers).
- *   build
- *     In releases, always 0.
- *     In snapshots, nearest Subversion revision. (It shouldn't be
- *     assumed that only one binary will have a given build number, of
- *     course.)
- *   revision
- *     Reserved; always 0.
- *
- * Examples of these version numbers:
- *   Release:  0.58.0.0	    (but 0.58 didn't have a VERSIONINFO resource)
- *   Snapshot: 0.58.6356.0  (between 0.58 and the next release)
- *   Local:    0.0.0.0
- */
-
-/*
- * Mechanics of version naming/numbering.
- * (This is a ripoff of ../version.c.)
- */
-
-#define STR1(x) #x
-#define STR(x) STR1(x)
-
-/* We keep this around even for snapshots, for monotonicity of version
- * numbering. It needs to be kept up to date. NB _comma_-separated. */
-#define BASE_VERSION 0,63
-
-#if defined SNAPSHOT
-
-/* Make SVN_REV mandatory for snapshots, to avoid issuing binary
- * version numbers that look like full releases. */
-#ifndef SVN_REV
-#error SVN_REV not defined/nonzero for snapshot build
-#endif
-
-#define VERSION_TEXT "Development snapshot " STR(SNAPSHOT) ":r" STR(SVN_REV)
-#ifdef MODIFIED
-#define BINARY_VERSION 0,0,0,0
-#else
-#define BINARY_VERSION BASE_VERSION,SVN_REV,0
-#endif
-
-#elif defined RELEASE
-
-#define VERSION_TEXT "Release " STR(RELEASE)
-#define BINARY_VERSION BASE_VERSION,0,0
-
-#elif defined PRERELEASE
-
-#define VERSION_TEXT "Pre-release " STR(PRERELEASE) ":r" STR(SVN_REV);
-#define BINARY_VERSION BASE_VERSION,SVN_REV,0
-
-#elif defined SVN_REV
-
-#define VERSION_TEXT "Custom build r" STR(SVN_REV)
-#ifdef MODIFIED
-#define BINARY_VERSION 0,0,0,0
-#else
-#define BINARY_VERSION BASE_VERSION,SVN_REV,0
-#endif
-
-#else
-
-/* We can't reliably get the same date and time as version.c, so
- * we won't bother trying. */
-#define VERSION_TEXT "Unidentified build"
-#define BINARY_VERSION 0,0,0,0
-
-#endif
+#include "version.h"
 
 /*
  * The actual VERSIONINFO resource.
@@ -97,7 +21,7 @@ FILEFLAGS	0x0L
 #if defined DEBUG
 		| VS_FF_DEBUG
 #endif
-#if defined SNAPSHOT
+#if defined SNAPSHOT || defined PRERELEASE
 		| VS_FF_PRERELEASE
 #elif !defined RELEASE
 		| VS_FF_PRIVATEBUILD
@@ -118,12 +42,12 @@ BEGIN
 	    VALUE "FileDescription",	APPDESC
 	    VALUE "InternalName",	APPNAME
 	    VALUE "OriginalFilename",	APPNAME
-	    VALUE "FileVersion",	VERSION_TEXT
-	    VALUE "ProductVersion",	VERSION_TEXT
+	    VALUE "FileVersion",	TEXTVER
+	    VALUE "ProductVersion",	TEXTVER
 	    VALUE "LegalCopyright",	"Copyright \251 1997-2014 Simon Tatham."
-#if (!defined SNAPSHOT) && (!defined RELEASE)
+#if (!defined SNAPSHOT) && (!defined RELEASE) && (!defined PRERELEASE)
 	    /* Only if VS_FF_PRIVATEBUILD. */
-	    VALUE "PrivateBuild",	VERSION_TEXT /* NBI */
+	    VALUE "PrivateBuild",	TEXTVER /* NBI */
 #endif
 	END
     END
@@ -133,7 +57,3 @@ BEGIN
 	VALUE "Translation", 0x809, 1200
     END
 END
-
-#undef VERSION_TEXT
-#undef BASE_VERSION
-#undef BINARY_VERSION