declarations allow fine-grained control of block compilation. These
declarations are only legal as a global declarations (
start-block declaration has this syntax:
When processed by the compiler, this declaration marks the start of block compilation, and specifies the entry points to that block. If no entry points are specified, then all functions are made into entry points. If already block compiling, then the compiler ends the current block and starts a new one.
end-block declaration has no arguments:
end-block declaration ends a block compilation unit without
starting a new one. This is useful mainly when only a portion of a file
is worth block compiling.