String cilkrts alert options

[kyle-singer]

Modify CILK_ALERT such that the method for enabling specific alert types is more memorable.
Still allows specifying just a number (as before), but will also accept a comma-separated list of options (excluding numbers).

For example, CILK_ALERT=fiber,closure enables ALERT_FIBER and ALERT_CLOSURE printouts from cilkrts_alert.

[kyle-singer]

Just noticed NOBUF was no longer used because I accidentally removed it. Need to fix.

[VoxSciurorum]

Can you rebase so the pull request contains your changes?

[VoxSciurorum]

I suggest strtok or strsep to break apart the string and bsearch of a table of (string, integer value) pairs instead of a series of strcmp calls. Or a linear search if that's simpler to code, but use a table.

[VoxSciurorum]

A few things look more complicated than necessary. See branch jfc/alert for simplifications.

1. Use the idiom sizeof X / sizeof X[0] (add parentheses to taste) to get the size of a constant array.

2. Use strcasecmp instead of converting a string to lower case.

3. Nested const is not necessary.

4. I don't see the need for the comma processing when using strtok. It is intended to be used in a simple loop without writing to any string. The simple loop on my branch works on my BSD-like systems.

    for (alert_str = strtok(alert_env, ","); alert_str;
         alert_str = strtok(NULL, ",")) {
             /* use alert_str */
    }

[kyle-singer]

Sorry, forgot to turn into a draft. I'm technically on vacation, and just tinkering a bit here and there. Latest commits were pre-coffee, so not the best.

1. Yep, this is what I wanted to do.
2. strcasecmp is not standard C, and I wanted this to be portable (hence why I also used strtok instead of strsep, despite strtok being awful).
3. Are you referring to putting const on name and mask_val as well as on the array?
4. strtok (per the man page) overwrites the delimiter token with '\0'. It is not technically necessary to reinsert the delimiter, but I don't want to actually modify the environment variable. Somebody could ostensibly want to use the environment variable elsewhere.

[VoxSciurorum]

2. The Single Unix Specification v4 includes strcasecmp.

3. Yes, if the object is declared const the struct members don't need to be const at top level.

4. I missed that. Use strdup to copy the environment variable and free it at the end.

[kyle-singer]

Re strcasecmp, I meant it isn't part of the C standard itself, though it is part of the Single Unix Specification v4, and I only find sources saying they are unable to use strcasecmp in Windows. Windows has a nearly identical function _stricmp, and working around using those case insensitive compare is clunky, so I don't mind using strcasecmp here.

Windows (allegedly) warns if you use strdup, and I think malloc + strcpy is better than the ifdefs that would be required for switching between strdup (Unix) and _strdup (Windows), so I am currently using malloc + strcpy instead of strdup.