* module/system/vm/program.scm (source:line-for-user): New exported
procedure, returns a 1-indexed line, suitable for presentation to a
user.
(write-program): Use source:line-for-user when making fallback names.
* module/system/vm/coverage.scm (coverage-data->lcov):
* module/language/assembly/disassemble.scm (source->string):
* module/system/repl/debug.scm (print-frame): Use source:line-for-user.
* libguile/vm.h (scm_c_vm_run): Make internal.
* libguile/vm.c (vm_default_engine): New static global variable.
(make_vm): Set vp->engine based on
(scm_vm_apply): Remove in favor of call-with-vm.
(scm_thread_vm, scm_set_thread_vm_x): Remove these, as they did not
have a well-defined meaning, and were dangerous to call on other
threads.
(scm_the_vm): Reinstate previous definition.
(symbol_to_vm_engine, vm_engine_to_symbol)
(vm_has_pending_computation): New helpers.
(scm_vm_engine, scm_set_vm_engine_x, scm_c_set_vm_engine_x): New
accessors for VM engines.
(scm_c_set_default_vm_engine_x, scm_set_default_vm_engine_x): New
setters for the default VM engine.
(scm_call_with_vm): New function, applies a procedure to arguments in
a context in which a given VM is current.
* libguile/eval.c (eval, scm_apply): VM dispatch goes through
scm_call_with_vm.
* test-suite/tests/control.test ("the-vm"):
* module/system/vm/coverage.scm (with-code-coverage): Use call-with-vm.
* module/system/vm/vm.scm: Update exports.
* test-suite/vm/run-vm-tests.scm (run-vm-program):
* test-suite/tests/compiler.test ("current-reader"): Just rely on the
result of make-program being an applicable.
* test-suite/tests/eval.test ("stack overflow"): Add a note that this
test does not test what it should.
* module/system/vm/coverage.scm (with-code-coverage): Switch current
thread to VM, using `set-thread-vm!'.
* test-suite/tests/coverage.test ("procedure-execution-count")["called
from C"]: New test.
