The libs which cmake controls are commented out at
include/freetype/config/ftoption.h
and cmake un-comment each enabled library, but the brotli option was
not commented out, therefore `FT_CONFIG_OPTION_USE_BROTLI' remained
defined even if brotli was missing/disabled/etc.
Comment it such that cmake can control it, which means leaving it
undefined if brotli is missing.
* include/freetype/config/ftoption.h: Fix typo.
cc17f852d5