Front-end can't handle character literals

[elazarg]

For example, handling the literal '*' results in

Exception in thread "main" java.lang.RuntimeException: I don't know how to handle const of type: ??? @ '*'
at ccomp.parser_hw.CCompiler.getConstant_(CCompiler.java:1895)
at ccomp.parser_hw.CCompiler.getConstant(CCompiler.java:1799)
at ccomp.parser_hw.CCompiler.getExpr(CCompiler.java:757)
at ccomp.parser_hw.CCompiler.getExpr(CCompiler.java:733)