Use $(bindir) for path to executable in mkmf

For the macOS -bundle_loader linker option, we need a path to the
Ruby exectuable. $(RUBY) is not necessarily a path since it could
be a command line invocation. That happens during build with
runruby.rb and can happen post installation if the user passes
the --ruby option to a extconf.rb. Use $(bindir) to locate
the executable instead.

Before installation, $(bindir) doesn't exist, so we need to be
able to override $(BUILTRUBY) in such situations so test-spec
and bundled extensions could build. Use a new mkmf global,
$builtruby, to do this; set it in fake.rb and in extmk.rb.

Our build system is quite complex...

1 files changed, 1 insertions, 1 deletions

diff --git a/ext/extmk.rb b/ext/extmk.rb
index 70067d28b8..b0d84ef00f 100755
--- a/ext/extmk.rb
+++ b/ext/extmk.rb
@@ -417,7 +417,6 @@ elsif CONFIG['EXTSTATIC']
 else
   $ruby = '$(topdir)/ruby' + EXEEXT
 end
-$mflags << "BUILTRUBY=#$ruby"
 $ruby = [$ruby]
 $ruby << "-I'$(topdir)'"
 unless CROSS_COMPILING
@@ -428,6 +427,7 @@ end
 topruby = $ruby
 $ruby = topruby.join(' ')
 $mflags << "ruby=#$ruby"
+$builtruby = '$(topdir)/ruby' + EXEEXT # Must be an executable path
 
 MTIMES = [__FILE__, 'rbconfig.rb', srcdir+'/lib/mkmf.rb'].collect {|f| File.mtime(f)}