A working h_drop_from which rewrites its underlying sequence as a sequence containing some ignored parsers.

also allow NULL argument for unamb_sub to mean default

I did this in a hurry, but it appears to work locally. I tested it with
a couple boring custom token type printers.

This BSD call will have to be implemented on windows. Right now
we have a stub that just exits the process.

We substitute H_GCC_ATTRIBUTE to any occurence of __attribute__ and
disable its function with non gcc, non clang compilers.

We use a H_ macro so as to not pollute users' namespaces.

On windows build without c4201 so as to allow anonymous struct. This
shows hammer is not C99 compliant but rather C11.

NEWS:
* Switching endianness mid-byte no longer potentially re-reads bytes.
* bit_offset now consistently refers to the number of bits already
  read.
* HParsedTokens now have a bit_length field; this is a size_t.  This
  may be removed for memory reasons.

The bit writer has not yet been updated to match; the result of
switching bit writer endianness in the middle of a byte remains
undefined.

It's causing unreferenced-variable warnings, and isn't referenced
anywhere aside from benchmark.c. If client code is likely to reference
it, perhaps move it into another header, so people who include hammer.h
don't have to refer to it to have warning-free code.

Import combinator and allocator APIs into SWIG. Next is glue. Need to fix unions in HParsedToken and HCaseResult.

Import combinator and allocator APIs into SWIG. Next is glue. Need to fix unions in HParsedToken and HCaseResult.