Log Message:
gd: updated to 2.3.1

2.3.1:

Fixed

Fix potential integer overflow detected by oss-fuzz
Fix 615 using libraqm
Fix 303: gdlib.pc: use Requires instead of Libs
Fixed 472: Adjusting CMakeLists.txt
Fix 615: gdImageStringFT() fails for empty strings as of libgd 2.3.0
Fix typo but preserve BC
Compute average in gdGuessBackgroundColorFromCorners properly
CMakeLists.txt: zlib is enabled implicitly
src/config.h.cmake: replace #cmakedefine01 with #define in macro ENABLE_GD_FOORMATS
gdlib.pc: use prefixes for pkgconfig file
cmake: remove required host includes
Move initial declaration out of for loop
distribute getlib script
Make gd_nnquant.c less likely to introduce duplicate definitions
webp: support pkg-config file
gd_io: replace internal Putchar with gdPutC
gd_io: trim unused Putword function

Added

Add REQUIRED to FIND_PACKAGE(ZLIB)
README: add some libraries info
VMS/README.VMS: Add dropping support information