Provide a valid NQP-home to the build dir rakudo runner

When building a relocatable rakudo, NQP-home is not set to a static value,
but determined dynamically based on the path of the program currently
running. This fails for the build dir runners, as they are not located in
the installation folder. We work around this, by setting the NQP_HOME env
variable to the NQP-home directory in the installation directory.

tools/build/create-jvm-runner.pl

@@ -118,10 +118,12 @@
     }
 }
 else {
+    my $nqp_home = File::Spec->catdir(abs_path($prefix), 'share', 'nqp');
+
     $preamble = join("\n",
         $preamble_unix,
         "$NQP_LIB",
-        ": \${NQP_HOME:=\"$static_nqp_home\"}",
+        "NQP_HOME=\"$nqp_home\"",
         ": \${NQP_JARS:=\"$nqpjars\"}",
         ": \${RAKUDO_HOME:=\"$prefix\"}",
         ": \${RAKUDO_JARS:=\"$rakudo_jars\"}",

tools/lib/NQP/Config/Rakudo.pm

@@ -161,6 +161,13 @@ sub configure_refine_vars {
         )
     );
 
+    $config->{nqp_home} = $self->nfp(
+        File::Spec->rel2abs(
+            $config->{nqp_home}
+              || File::Spec->catdir( $config->{'prefix'}, 'share', 'nqp' )
+        )
+    );
+
     $config->{static_rakudo_home} =
       $config->{relocatable} eq 'reloc'
       ? ''

tools/templates/moar/Makefile.in

@@ -123,7 +123,8 @@ $(R_SETTING_MOAR): @bsm(RAKUDO)@@for_specs( @bsm(SETTING_@ucspec@)@)@ $(R_SETTIN
 		--set-var=base_dir=@shquot(@nfp(@base_dir@)@)@ \
 		--set-var=nqp_lib_dir=@shquot(@nfp(@nqp::libdir@)@)@ \
 		--set-var=exec_name=@shquot(@nfp(@base_dir@/@bpm(RUNNER)@)@)@ \
-		--set-var=mbc=@bsm(RAKUDO)@
+		--set-var=mbc=@bsm(RAKUDO)@ \
+		--set-var=nqp_home=@shquot(@nfp(@nqp_home@)@)@
 	$(NOECHO)@bpm(CC)@ @moar::ccswitch@ @bpm(CFLAGS)@ @moar::ccout@rakudo-m@moar::obj@ rakudo-m.c
 	$(NOECHO)@bpm(LD)@ @moar::ldout@$@ @bpm(LDFLAGS)@ @bpm(MINGW_UNICODE)@ rakudo-m@moar::obj@
 

tools/templates/moar/rakudo-m-build.c.in

@@ -35,6 +35,8 @@ int main(int argc, char *argv[])
 
     exec_argv[exec_argc - 1] = NULL;
 
+    setenv("NQP_HOME", "@c_escape(@nfp(@nqp_home@)@)@", 1);
+
     // Hack: Explicitly set a dummy RAKUDO_HOME, so the autogenerated
     // CompUnitRepo folder structure does not end up in the build directories
     // parent folder.

tools/templates/moar/rakudo-m-build.c.windows

@@ -119,6 +119,8 @@ int wmain(int argc, wchar_t *argv[]) {
     }
     cmd_line[cmd_line_size - 1] = 0;
 
+    _wputenv_s(L"NQP_HOME", L"@c_escape(@nfp(@nqp_home@)@)@");
+
     // Hack: Explicitly set a dummy RAKUDO_HOME, so the autogenerated CompUnitRepo
     // folder structure does not end up in the build directories parent folder.
     _wputenv_s(L"RAKUDO_HOME", L"@c_escape(@nfp(@base_dir@/gen/build_rakudo_home)@)@");