The space a Text has for saving the string is allocated in chunks. To
request additional space SH_Text_enlarge is called. If the requestad
size fits inside the already allocated space or is even smaller than the
current size, nothing is done. Otherwise a multiple of chunk size is
allocated beeing equal or greater than the requested size. The chunk
size can be changed by changing the macro CHUNK_SIZE in src/text.h. The
default is 64.
This adjustment is done automatically when a string is added.