When writing this command line

sudo C_INCLUDE_PATH=/usr/local/opt/openssl/include /Applications/XAMPP/xamppfiles/bin/pecl install mongodb

I get this error.

fatal error: 'unicode/usprep.h' file not found
#include <unicode/usprep.h>
         ^~~~~~~~~~~~~~~~~~
1 error generated.
make: *** [src/libmongoc/src/libmongoc/src/mongoc/mongoc-scram.lo] Error 1
ERROR: `make' failed

It says something with the usprep.h, it took for me days to figure out in many different ways but unfortunately you guys may support me to solve it.