#792 Special variables for inline assembly

[Sebastian Riedel]

It might be handy to allow special local labels for inline assembly. Which just get translated to a local label managed by the compiler, with scope bing limited to one inline __asm.

Something like:

__asm
label$:
    ld b, b
    jr label$
__endasm;

This allows:

• usage of names without breaking generated jumps (see [bugs:#2831])
• inline asm with labels in C macros, which might be used multiple times in a function