[PATCH] winebuild: Use $CCAS to assemble if found

[Alexandre Rostovtsev]

On Sun, 2013-02-03 at 20:27 -0700, Charles Davis wrote:
> If the user doesn't set CCAS--which she doesn't the majority of the time--configure will pick up the first of {clang, gas, as} in the PATH. Are you sure that's what you want?

I had attempted to preserve the behavior that exists in wine-1.5.23 by
default because I assumed there was some good reason for it (even though
I could not see it). But if you agree that behavior was undesirable,
then of course it would be better to change the order depending on the
platform, and check for {clang, gas, as} on OSX, and {gas, as, clang} on
other platforms.

> Perhaps we should just not define CCAS if the user didn't specify it. Then below, you can wrap the block you added in an #ifdef.

My patch skips the CCAS block if strlen( CCAS ) == 0, which is basically
equivalent to what you propose.

> You may recall that one of the earlier versions (later than the one that detected Clang in configure) used strstr(3) to detect Clang; I was then told not to use it. I suspect this is because some systems' strstr(3) exhibits quadratic-time behavior. I don't know if you can avoid that in this case, though. Maybe you can just grab the basename and strip off the CTARGET prefix; then you should just be able to do a strcmp(3). Or am I missing something?

Even if strstr(x,y) is quadratic in strlen(x) and strlen(y), here it is
being called on two *constant* strings: CCAS and "clang". So the runtime
penalty is in fact constant :)

But it's probably better to avoid this penalty altogether. For example,
by checking in configure whether CCAS is Clang or GAS, and defining an
appropriate flag.

-Alexandre.