remade the build model to be more proto-friendly

I started by copying proto's model right off, but there were a number of subtle
improvements that I wanted to make, namely:

 - Renamed Configure.p6 -> configure

 - Copied Configure.pm from proto into druid, so that druid doesn't have to
   depend on proto. See commit 7cff8e945cf30a2cac9794d01a803f688050f0bb in
   proto.

 - I don't care for the lib/Test.pir target. Instead, I added RAKUDO_DIR to
   PERL6LIB; feels cleaner.

 - I don't care for Configure.pm running make. Changed the comment to let
   the user do it herself.

 - added 'env' commands to set the PERL6LIB variable both in target 'all' and
   in target 'test'.

Makefile.in

@@ -1,4 +1,6 @@
-PARROT_DIR=<PARROT_DIR>
+PERL6=<PERL6>
+RAKUDO_DIR=<RAKUDO_DIR>
+PERL6LIB='<PERL6LIB>:$(RAKUDO_DIR)'
 
 SOURCES=lib/Druid/Base.pm lib/Druid/Game/Observer.pm \
         lib/Druid/Game/Subject.pm lib/Druid/Game.pm lib/Druid/View.pm \
@@ -11,10 +13,10 @@ PIRS=$(SOURCES:.pm=.pir)
 all: $(PIRS)
 
 %.pir: %.pm
-	$(PARROT_DIR)/parrot \
-        $(PARROT_DIR)/languages/rakudo/perl6.pbc \
-        --target=pir --output=$@ \
-        $<
+	env PERL6LIB=$(PERL6LIB) $(PERL6) --target=pir --output=$@ $<
 
 clean:
-	rm -f $(PIRS) Makefile
+	rm -f $(PIRS)
+
+test: all
+	env PERL6LIB=$(PERL6LIB) prove -e '$(PERL6)' -r --nocolor t/

README

@@ -42,13 +42,11 @@ Yup, you're ready to go.
 
 (After all, compilation does make startup a little faster.)
 
-% perl Makefile.PL
+% perl6 configure
 % make
 
 Remember that you still need to set $PERL6LIB and $PARROT_DIR as above. The
-file Makefile.PL will complain if you don't. The 'make' process, should you
-foolishly proceed to it without heeding Makefile.PL's advice, will not
-complain, just fail.
+configure script will complain if you don't.
 
 == Installing via proto
 

configure

@@ -0,0 +1,3 @@
+#!perl6
+use v6;
+use Configure;

lib/Configure.pm

@@ -0,0 +1,141 @@
+# Configure.pm
+
+.say for
+    '',
+    'Configure.pm is preparing to make your Makefile.',
+    '';
+
+# Determine how this Configure.p6 was invoked, to write the same paths
+# and executables into the Makefile variables. The variables are:
+# PERL6       how to execute a Perl 6 script
+# PERL6LIB    initial value of @*INC, where 'use <module>;' searches
+# PERL6BIN    directory where executables such as 'prove' reside
+# RAKUDO_DIR  (deprecated) currently the location of Rakudo's Test.pm
+
+my $parrot_dir = %*VM<config><build_dir>;
+my $rakudo_dir;
+my $perl6;
+
+regex parrot_in_rakudo { ( .* '/rakudo' ) '/parrot' }
+
+# There are two possible relationships between the parrot and rakudo
+# directories: rakudo/parrot or parrot/languages/rakudo
+if $parrot_dir ~~ / <parrot_in_rakudo> / {
+    # first case, rakudo/parrot for example if installed using new
+    # 'git clone ...rakudo.git' then 'perl Configure.pl --gen-parrot'
+    $rakudo_dir = $parrot_dir.subst( / '/parrot' $ /, ''); #'
+}
+elsif "$parrot_dir/languages/rakudo" ~~ :d {
+    # second case, parrot/languages/rakudo if installed the old way
+    $rakudo_dir = "$parrot_dir/languages/rakudo";
+}
+else { # anything else 
+    .say for
+        "Found a PARROT_DIR to be $parrot_dir",
+        'but there is no Rakudo nearby. Please contact the proto people.',
+        '';
+    exit(1);
+}
+if "$rakudo_dir/perl6" ~~ :f or "$rakudo_dir/perl6.exe" ~~ :f {
+    $perl6 = "$rakudo_dir/perl6";  # the fake executable from pbc_to_exe
+}
+else {
+    $perl6 = "$parrot_dir/parrot $rakudo_dir/perl6.pbc";
+}
+
+say "PERL6       $perl6";
+my $perl6lib = %*ENV<PWD> ~ '/lib';
+say "PERL6LIB    $perl6lib";
+# The perl6-examples/bin directory is a sibling of PERL6LIB
+my $perl6bin = $perl6lib.subst( '/lib', '/bin' );
+say "PERL6BIN    $perl6bin";
+say "RAKUDO_DIR  $rakudo_dir";
+
+# Read Makefile.in, edit, write Makefile
+my $maketext = slurp( 'Makefile.in' );
+$maketext .= subst( .key, .value ) for
+    'Makefile.in'       => 'Makefile',
+    'To be read'        => 'Written',
+    'replaces <TOKENS>' => 'defined these',
+# Maintainer note: keep the following in sync with pod#VARIABLES below
+    '<PERL6>'           => $perl6,
+    '<PERL6LIB>'        => $perl6lib,
+    '<PERL6BIN>'        => $perl6bin,
+    '<RAKUDO_DIR>'      => $rakudo_dir;
+squirt( 'Makefile', $maketext );
+
+# Job done.
+.say for
+    '',
+    q[Makefile is ready. Ready to run 'make'.];
+
+
+# The opposite of slurp
+sub squirt( Str $filename, Str $text ) {
+    my $handle = open( $filename, :w )
+        or die $!;
+    $handle.print: $text;
+    $handle.close;
+}
+
+# This Configure.pm can work with the following ways of starting up:
+# 1. The explicit way Parrot runs any Parrot Byte Code:
+#    /my/parrot/parrot /my/rakudo/perl6.pbc Configure.p6
+# 2. The Rakudo "Fake Executable" made by pbc_to_exe:
+#    /my/rakudo/perl6 Configure.p6
+# The rest are variations of 1. and 2. to sugar the command line:
+# 3. A shell script perl6 for 1: '/my/parrot/parrot /my/rakudo/perl6.pbc $*':
+#    /my/perl6 Configure.p6    # or 'perl6 Configure.p6' with search path
+# 4. A shell alias for 1: perl6='/my/parrot/parrot /my/rakudo/perl6.pbc':
+#    perl6 Configure.p6
+# 5. A symbolic link for 2: 'sudo ln -s /my/rakudo/perl6 /bin':
+#    perl6 Configure.p6
+
+# Do you know of another way to execute Perl 6 scripts? Please tell the
+# maintainers.
+
+=begin pod
+
+=head1 NAME
+Makefile.pm - common code for Makefile builder and runner
+
+=head1 SYNOPSIS
+
+ perl6 Configure.p6
+
+Where F<Configure.p6> generally has only these lines:
+
+ # Configure.p6 - installer - see documentation in ../Configure.pm
+ use v6; BEGIN { @*INC.push( '../..' ); }; use Configure; # proto dir
+
+=head1 DESCRIPTION
+A Perl module often needs a Makefile to specify how to build, test and
+install it. A Makefile must make sense to the Unix C<make> utility.
+Makefiles must often be adjusted slightly to alter the context in which
+they will work. There are various tools to "make Makefiles" and this
+F<Configure.p6> and F<Configure.pm> combination run purely in Perl 6.
+
+Configure.p6 resides in the module top level directory. For covenience,
+Configure.p6 usually contains only the lines shown in L<doc:#SYNOPSIS>
+above, namely a comment and one line of code to pass execution to
+F<Configure.pm>. Any custom actions to prepare the module can be called
+by the default target in Makefile.in.
+
+Configure.pm reads F<Makefile.in> from the module top level directory,
+replaces certain variables marked like <THIS>, and writes the updated
+text to Makefile in the same directory. Finally it runs the standard
+'make' utility, which builds the first target defined in Makefile.
+
+=head1 VARIABLES
+C<Configure.p6> will cause the following tokens to be substituted when
+creating the new F<Makefile>:
+
+ <PERL6>        pathname of Perl 6 (fake)executable
+ <PERL6LIB>     lib/ directory of the installed project
+ <PERL6BIN>     bin/ directory of the installed project
+ <RAKUDO_DIR>   whence Rakudo's Test.pm can be compiled
+
+=head1 AUTHOR
+Martin Berends (mberends on CPAN github #perl6 and @autoexec.demon.nl).
+
+=end pod