I suggest that Cristofer submit the information requested in the manual:
https://gmplib.org/manual/Reporting-Bugs
In particular, they should send
* The version of gmp they are using.
* The output produced by running './configure', when building gmp. They
should show
any options that they m
Most likely you need to use the command
sudo make install
and you will be prompted to type in the password for "root" (also known as
the "superuser" or "administrator") -- "sudo" stands for "superuser do".
As it is, you probably do not have permission to create the directory
because you are NOT