Ccache refusing to cache

Hi,

I've installed ccache 3.1.9 on my Archlinux system and made symbolic links:

$   ls -la /usr/local/bin
lrwxrwxrwx  1 root root       15 29 mag 11.41 c++ -> /usr/bin/ccache
lrwxrwxrwx  1 root root       15 29 mag 11.41 cc -> /usr/bin/ccache
lrwxrwxrwx  1 root root       15 29 mag 11.41 g++ -> /usr/bin/ccache
lrwxrwxrwx  1 root root       15 29 mag 11.41 gcc -> /usr/bin/ccache

then I modified the CMakeCache.txt on my project using this:

//CXX compiler.
CMAKE_CXX_COMPILER:FILEPATH=/usr/local/bin/g++

then I did a make. I know (or I believe) that Ccache caches the compiled files:

$ ccache -s
cache directory                     /home/manganelll/.ccache
cache hit (direct)                    71
cache hit (preprocessed)               2
cache miss                          1700
called for link                      116
files in cache                      9426
cache size                           3.3 Gbytes
max cache size                       5.0 Gbytes


but everytime I compile this source code, after a "git pull", the
cache is never used (I see that it increments only the "files in
cache" value).

Any hint? Thank you in advance.
Luca