Incorporate some git information into NetHack

Incorporate some git information into NetHack so that it
is potentially visible to a player. That's useful when
collecting details about the version that they are
running and, if the gitinfo is present, it can tie the
code to a specific git commit in the repository.

This modifies 'makedefs -v' to check for the presence of a data file
called dat/gitinfo.txt and if it is there, parse out its
contents, then write additional lines to include/date.h beyond
what 'makedefs -v' was previously putting in there, similar to
this sample:

      #define NETHACK_GIT_SHA "0c84e564c78e2024e562d39539376ce2e21eec8e"
      #define NETHACK_GIT_BRANCH "NetHack-3.6.0"

The contents of an appropriate dat/gitinfo.txt are as follows,
and trailing/leading whitespace is not significant:

      githash = 0c84e564c78e2024e562d39539376ce2e21eec8e
      gitbranch = NetHack-3.6.0

It also adjusts the contents of the 'v' version information to
include the additional git info when available.

Also adds some hooks DEVEL/hooksdir and a perl file to DEVEL
for simplifying and automating the deposit of dat/gitinfo.txt
so that it generally reflects the most current git commit.

DEVEL/gitinfo.pl can be used to build dat/gitinfo.txt at any
time without doing a commit, merge, or checkout.
    	perl DEVEL/gitinfo.pl

command line --version and -version support

To complement the extra information being provided in the
version by the 'v' command, this also adds support for the
following new command line arguments:
    --version
     -version            Output the NetHack version string then exit.

    --version:paste      Output the NetHack version string and also copy it to
     -version:paste      the platform's paste buffer for insertion somewhere,
                         then exit.

If the paste variation of -version is requested on a platform that
hasn't incorporated any support for the capability, it will deliver
the version info then an error message, prior to exiting.

To support the extended -version:paste variation, a port needs to:
    - provide a port-specific routine to perform
      the paste buffer copy in a port code file.
    - #define RUNTIME_PASTEBUF_SUPPORT in the include/portconf.h header file.

    --skeleton--
    void port_insert_pastebuf(buf)
    char *buf;
    {
    	/* insert code to copy the version info from buf into
    	   platform's paste buffer in a supported way */
    }

macosx and Windows have both added support for RUNTIME_PASTEBUF_SUPPORT

DEVEL/hooksdir/NHgithook.pm

@@ -60,6 +60,36 @@ sub POST {
 	&do_hook("POST");
 }
 
+###
+### store githash and gitbranch in dat/gitinfo.txt
+###
+
+sub nhversioning {
+    use strict;
+    use warnings;
+
+    my $git_sha = `git rev-parse HEAD`;
+    $git_sha =~ s/\s+//g;
+    my $git_branch = `git rev-parse --abbrev-ref HEAD`;
+    $git_branch =~ s/\s+//g;
+
+    if (open my $fh, '<', 'dat/gitinfo.txt') {
+        while(my $line = <$fh>) {
+            if ((index $line, $git_sha) >= 0) {
+                close $fh;
+                print "No update made to dat/gitinfo.txt, existing githash=".$git_sha."\n";
+                return;
+            }
+        }
+        close $fh;
+    }
+    if (open my $fh, '>', 'dat/gitinfo.txt') {
+        print $fh 'githash='.$git_sha."\n";
+        print $fh 'gitbranch='.$git_branch."\n";
+        print "An updated dat/gitinfo.txt was written, githash=".$git_sha."\n";
+    }
+}
+
 # PRIVATE
 sub do_hook {
 	my($p) = @_;

DEVEL/hooksdir/post-checkout

@@ -26,5 +26,6 @@ use NHgithook;
 #STARTUP-END
 
 &NHgithook::PRE;
+&NHgithook::nhversioning;
 &NHgithook::POST;
 exit 0;

DEVEL/hooksdir/post-commit

@@ -26,5 +26,6 @@ use NHgithook;
 #STARTUP-END
 
 &NHgithook::PRE;
+&NHgithook::nhversioning;
 &NHgithook::POST;
 exit 0;

DEVEL/hooksdir/post-merge

@@ -22,9 +22,11 @@ BEGIN {
     chomp $gitdir;
     push(@INC, $gitdir.$PDS."hooks");
 }
+
 use NHgithook;
 #STARTUP-END
 
 &NHgithook::PRE;
+&NHgithook::nhversioning;
 &NHgithook::POST;
 exit 0;