I get linker errors without it because libgit2.pc isn't giving all the libraries needed. For example:

```
$ pkg-config --static --libs libgit2
-Wl,-Bsymbolic-functions -Wl,-z,relro -L/usr/local/lib -lrt -lgit2 -lssl -lcrypto -ldl -lz -lssh2 -lgcrypt  
```

```
$ pkg-config --libs libgit2
-L/usr/local/lib -lgit2  
```