feat(fortran): Fortran interface can now use multi-zone

Fortran interface uses the new C api ability to call the naieve
multi-zone solver. This allows fortran calling code to make use of in
build parellaism for solving multiple zones

tools/meson.build

@@ -1,4 +1,5 @@
 if get_option('build_tools')
-    subdir('config')
-    subdir('cli')
+    subdir('gf_config')
+    subdir('gf_quick')
+    subdir('gf_multi')
 endif