* 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.
* test-suite/tests/coverage.test ("line-execution-counts")["several times"]: Add missing `else' clause.
* module/system/vm/coverage.scm: New file. * module/Makefile.am (SYSTEM_SOURCES): Add `system/vm/coverage.scm'. * test-suite/guile-test (main): Use (system vm coverage). Handle `--coverage' and `-c'. * test-suite/tests/coverage.test: New file. * test-suite/Makefile.am (SCM_TESTS): Add `tests/coverage.test'. * doc/ref/Makefile.am (guile_TEXINFOS): Add `api-coverage.texi'. * doc/ref/api-coverage.texi: New file. * doc/ref/guile.texi (API Reference): Include it.