Support for boolean values in libjansson

tests/runner.py ALL.test_jansson
Running all test modes on test "test_jansson"
test_jansson (test_core.default) ... (checking sanity from test runner)
INFO     root: (Emscripten: Running sanity checks)
ok
test_jansson (test_core.asm1) ... ok
test_jansson (test_core.asm2) ... ok
test_jansson (test_core.asm3) ... ok
test_jansson (test_core.asm2f) ... ok
test_jansson (test_core.asm2g) ... <skipping: jansson is not safe-heap safe> ok
test_jansson (test_core.asm3i) ... ok
test_jansson (test_core.slow2) ... INFO     root: =======================================
INFO     root: bootstrapping relooper...
INFO     root:   bootstrap phase 1
clang-3.3: warning: argument unused during compilation: '-nostdinc++'
INFO     root:   bootstrap phase 2
clang-3.3: warning: argument unused during compilation: '-nostdinc++'
INFO     root: bootstrapping relooper succeeded
INFO     root: =======================================
ok
test_jansson (test_core.slow2asm) ... ok

----------------------------------------------------------------------
Ran 9 tests in 119.249s

OK