Create `box' on `make all'.
* box-module/check.test, box-dynamic-module/check.test,
* box-dynamic/check.test: New files.
* box-dynamic/Makefile.am (libbox): Create box library on `make
all'.
(TESTS): New variable.
* box/Makefile.am (TESTS): New variable.
Create `box' program on `make all', use freshly built Guile for
building.
* box/check.test: New file.
* modules/check.test, safe/check.test, scripts/check.test: Set
GUILE_LOAD_PATH to make the tests run without installed Guile.