RFR: Various fixed for system header

[Henry Jen]

Hi,

Please review a webrev[1] that

1. Enable generate code for system header files with an —system switch.
2. Instead of throwing exception at binding time for not existing symbol in a native library, allow binder to pass and generate NoSuchMethodException on invocation of the method.
3. A minor fix for MacroParser that failed if a macro definition has $ character.

These are minor tweaks but I think worth some discussion on how we deal with system header files and non-matched symbols.

[1] http://cr.openjdk.java.net/~henryjen/panama/foreign/notExistSymbol/webrev/

Cheers,
Henry