malloc(): corrupted top size #1

Strange malloc bugs occur when parsing the config file.

I tried to find a minimal configuration that causes the malloc bugs I experienced: You need to have at least two lines that are not comments or blank and one line with a 26-character command to get this:

malloc.c:2379: sysmalloc: Assertion '(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.

Try for example:

    * MUTE:
    * MUTE:
    * MUTE: abcdefghijklmnopqrstuvwxyz

If you give a command longer than 26 characters, you get this error:

malloc(): corrupted top size

Try for example:

    * MUTE:
    * MUTE:
    * MUTE: abcdefghijklmnopqrstuvwxyza

I'm not quite sure why the malloc bug occurs and valgrid didn't give me much useful information, but the parser should not allow for blank command or keys values.
I added a check for it and the problem should no longer occur.