Make C, C++, D, Java, Groovy compilers customizable

	* 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

lisp/ob-C.el

@@ -46,16 +46,32 @@
 
 (defvar org-babel-default-header-args:C '())
 
-(defvar org-babel-C-compiler "gcc"
-  "Command used to compile a C source code file into an
-executable.")
-
-(defvar org-babel-C++-compiler "g++"
-  "Command used to compile a C++ source code file into an
-executable.")
-
-(defvar org-babel-D-compiler "rdmd"
-  "Command used to compile and execute a D source code file.")
+(defcustom org-babel-C-compiler "gcc"
+  "Command used to compile a C source code file into an executable.
+May be either a command in the path, like gcc
+or an absolute path name, like /usr/local/bin/gcc
+parameter may be used, like gcc -v"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
+
+(defcustom org-babel-C++-compiler "g++"
+  "Command used to compile a C++ source code file into an executable.
+May be either a command in the path, like g++
+or an absolute path name, like /usr/local/bin/g++
+parameter may be used, like g++ -v"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
+
+(defcustom org-babel-D-compiler "rdmd"
+  "Command used to compile and execute a D source code file.
+May be either a command in the path, like rdmd
+or an absolute path name, like /usr/local/bin/rdmd
+parameter may be used, like rdmd --chatty"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
 
 (defvar org-babel-c-variant nil
   "Internal variable used to hold which type of C (e.g. C or C++ or D)

lisp/ob-groovy.el

@@ -36,8 +36,14 @@
 (defvar org-babel-tangle-lang-exts) ;; Autoloaded
 (add-to-list 'org-babel-tangle-lang-exts '("groovy" . "groovy"))
 (defvar org-babel-default-header-args:groovy '())
-(defvar org-babel-groovy-command "groovy"
-  "Name of the command to use for executing Groovy code.")
+(defcustom org-babel-groovy-command "groovy"
+  "Name of the command to use for executing Groovy code.
+May be either a command in the path, like groovy
+or an absolute path name, like /usr/local/bin/groovy
+parameters may be used, like groovy -v"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
 
 (defun org-babel-execute:groovy (body params)
   "Execute a block of Groovy code with org-babel.  This function is

lisp/ob-java.el

@@ -32,11 +32,23 @@
 (defvar org-babel-tangle-lang-exts)
 (add-to-list 'org-babel-tangle-lang-exts '("java" . "java"))
 
-(defvar org-babel-java-command "java"
-  "Name of the java command.")
-
-(defvar org-babel-java-compiler "javac"
-  "Name of the java compiler.")
+(defcustom org-babel-java-command "java"
+  "Name of the java command.
+May be either a command in the path, like java
+or an absolute path name, like /usr/local/bin/java
+parameters may be used, like java -verbose"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
+
+(defcustom org-babel-java-compiler "javac"
+  "Name of the java compiler.
+May be either a command in the path, like javac
+or an absolute path name, like /usr/local/bin/javac
+parameters may be used, like javac -verbose"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
 
 (defun org-babel-execute:java (body params)
   (let* ((classname (or (cdr (assoc :classname params))