rb-pkg-config, rb19-pkg-config: portindex fails

[ryandesign (Ryan Carsten Schmidt)]

portindex fails to index rb-pkg-config and rb19-pkg-config unless gem and gem1.9 are already installed, respectively:

$ sudo port -v sync
--->  Updating the ports tree
Synchronizing local ports tree from file:///Volumes/Data/macports/dports
Updating '/Volumes/Data/macports/dports':
At revision 112784.
Creating port index in /Volumes/Data/macports/dports
Failed to parse file ruby/rb-pkg-config/Portfile: can't read "ruby.gemdir": couldn't execute "/Volumes/Data/macports/leopard/libexec/ruby1.8/gem": no such file or directory
Failed to parse file ruby/rb19-pkg-config/Portfile: can't read "ruby.gemdir": couldn't execute "/Volumes/Data/macports/leopard/bin/gem1.9": no such file or directory

Total number of ports parsed:	2 
Ports successfully parsed:	0 
Ports failed:			2 
Up-to-date ports skipped:	17808

[ryandesign (Ryan Carsten Schmidt)]

r112791