Add triggers to notify InnoDB developers when MySQL developers change files

that they control.


BitKeeper/triggers/post-commit.innodb.pl:
  Trigger to notify InnoDB developers about changes in InnoDB
  files.
BitKeeper/triggers/post-incoming.innodb.pl:
  Trigger to notify InnoDB developers about changes in InnoDB
  files.
BitKeeper/triggers/pre-commit.innodb.pl:
  Trigger to warn MySQL developers that they have changed InnoDB files,
  and that their changes will be sent to the InnoDB developers if they
  choose to commit.
BitKeeper/triggers/triggers-lib.pl:
  Utility functions for BK triggers written in Perl.

BitKeeper/triggers/pre-commit.innodb.pl

@@ -0,0 +1,21 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use FindBin;
+require "$FindBin::Bin/triggers-lib.pl";
+
+die "$0: Script error: \$BK_PENDING is not set in pre-commit trigger\n"
+  unless defined $ENV{BK_PENDING};
+
+# Read changed files from $BK_PENDING directly.  Do not bother user about
+# merge changes; they don't have any choice, the merge must be done.
+my $changes = innodb_get_changes('file', $ENV{BK_PENDING}, undef)
+  or exit 0;
+
+innodb_inform_and_query_user($changes)
+  or exit 1;  # Abort commit
+
+# OK, continue with commit
+exit 0;