Boot core library from image rather than source

This should speed up start time and reduce malloc/free
usage to about 15% of what is what previously for startup.
The current cost is slightly larger binary as the representaion
of the image is currently less compact than source code.

src/boot/boot.c

@@ -0,0 +1,43 @@
+/*
+* Copyright (c) 2019 Calvin Rose
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to
+* deal in the Software without restriction, including without limitation the
+* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+* sell copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+* IN THE SOFTWARE.
+*/
+
+#include <janet/janet.h>
+
+extern const unsigned char *janet_gen_boot;
+extern int32_t janet_gen_boot_size;
+
+int main() {
+    int status;
+    JanetTable *env;
+
+    /* Set up VM */
+    janet_init();
+    env = janet_core_env();
+
+    /* Run bootstrap script to generate core image */
+    status = janet_dobytes(env, janet_gen_boot, janet_gen_boot_size, "boot.janet", NULL);
+
+    /* Deinitialize vm */
+    janet_deinit();
+
+    return status;
+}