The cJSON (not to be confused with JSON-C which fulfills the same purpose but with a different API) package provides a light-weight JSON parser ibrary in C.
Apply a patch to fix several security vulnerabilties and other issues:
patch -Np1 -i ../cJSON-1.7.19-upstream_fixes-1.patch
Install cJSON by running the following commands:
mkdir build &&
cd build &&
cmake -D CMAKE_INSTALL_PREFIX=/usr \
-D CMAKE_BUILD_TYPE=Release \
-G Ninja .. &&
ninja
Now, as the root user:
ninja install