errors building some tests using clang compiler

[carns]

If you compile the aesop tree using clang as the underlying compiler (../configure CC=clang) then everything works except for three specific test programs:

• tests/blocking-overhead
• parser/tests/blocking/nbfun
• parser/tests/blocking/lonely-pbranch3

In all three cases the error looks something like this:

../tests/blocking-overhead.ae:65:5: error: indirect goto in function with no address-of-label expressions
    goto * (__ae_ctl->gen.state_label);
    ^

The translator is emitting boilerplate code that includes jumping to a label pointer, but the function doesn't have any blocking calls or label pointers.

This ticket isn't critical; clang is mainly of interest for some analysis and debugging tools and the above tests can be commented out.

[dkimpe]

Fixed in 81c56af54c10f4d600d5e05b63fb603b0e053159 by always emitting at least one label in the function body.