* ob-C.el (org-babel-C-compiler): (org-babel-C++-compiler): (org-babel-D-compiler): changed defvar to defcustom * ob-java.el (org-babel-java-command): (org-babel-java-compiler): changed defvar to defcustom * ob-groovy.el (org-babel-groovy-command): changed defvar to defcustom