[Xastir] compiling and installing xastir using git on a Raspberri pi

[Menga]

Dear friends,
I'm reinstalling xastir on a fresh 2018-04-18-raspbian-stretch on my new RPI 
3 B+ using git.
In the past adventurousy I was able to compile the program starting from the 
source files.
This time I want to go through the git, because I will customize the 
program.

Following step by step the GIT instructions at arrive at ../configure.
The system says: File or Directory not found.
What next?
Giuseppe
IZ1GCL