* bc-int.h (yasm_bytecode_callback): Add reserve flag to indicate if the
bytecode outputs just space and not data.
* bytecode.pxi: Update to match.
* bytecode.c (yasm_bc_tobytes): Use reserve flag instead of checking
against bytecode_reserve as special case.
* dwarf2-info.c, dwarf2-line.c, dwarf2-dbgfmt.c, cv-symline.c, cv-type.c,
* stabs-dbgfmt.c, lc3bbc.c, x86bc.c: Update to set reserve=0.
* bc-align.c, bc-insn.c, bc-reserve.c, bc-org.c, bc-incbin.c, bc-data.c,
* bytecode.c: Split out bytecodes into separate files. While we're here,
merge LEB128 into general data bytecode.