bug#54444: wrong .pc file for `configure --disable-shared`

[guile 2.2.7]


If I configure guile with

```
configure --disable-shared
```

the created `guile-2.2.pc` is incorrect: Instead of

```
Libs: -L${libdir} -lguile-2.2 -lgc
Libs.private: -lgmp -lltdl -L/usr/lib64/../lib64 -lffi \
              -lunistring -lcrypt  -lm
```

it should have

```
Libs: -L${libdir} -lguile-2.2 -lgc \
      -lgmp -lltdl -L/usr/lib64/../lib64 -lffi \
      -lunistring -lcrypt  -lm
```

IMHO the user must not be forced to know how guile was installed.  Or
to say it differently: It's not the job of an application's
`configure` script to find out whether it has to pass the `--static`
keyword to `pkg-config` if it just wants to link to guile in general.


    Werner