Lack of support of link arguments in C and C++ languages

[kcleung]

In C and C++ programs that requires external libraries, the link arguments must be inserted after the output file argument, e.g.:

g++ -g -W -Wall foo.cpp -o foo -lGl -Glu

or otherwise the linker will not be able to load the requested libraries, yet the current jobe version only supports "compileargs".

To fix this problem, I have added the parameter "linkargs" in run_spec to allow specification of link arguments. The fix is in:
https://github.com/UoA-CompSci/jobe

and I have already submitted a pull request. Please have a look.