Change build options for emscripten.

Makefile

@@ -107,7 +107,8 @@ $(JANET_LIBRARY): $(JANET_CORE_OBJECTS)
 ######################
 
 EMCC=emcc
-EMCCFLAGS=-std=c99 -Wall -Wextra -Isrc/include -fpic -O2 -s EXTRA_EXPORTED_RUNTIME_METHODS='["cwrap"]'
+EMCCFLAGS=-std=c99 -Wall -Wextra -Isrc/include -fpic -O2 -s EXTRA_EXPORTED_RUNTIME_METHODS='["cwrap"]' \
+		  -s ALLOW_MEMORY_GROWTH=1 -s WASM=1
 JANET_EMTARGET=janet.js
 JANET_WEB_SOURCES=$(JANET_CORE_SOURCES) $(JANET_WEBCLIENT_SOURCES)
 JANET_EMOBJECTS=$(patsubst %.c,%.bc,$(JANET_WEB_SOURCES))

src/include/janet/janet.h

@@ -96,6 +96,8 @@ extern "C" {
 /* Check emscripten */
 #ifdef __EMSCRIPTEN__
 #define JANET_NO_DYNAMIC_MODULES
+#define JANET_NO_NANBOX
+#define JANET_WALIGN 8
 #endif
 
 /* Define how global janet state is declared */
@@ -180,11 +182,13 @@ extern "C" {
 #endif
 
 /* Alignment for pointers */
+#ifndef JANET_WALIGN
 #ifdef JANET_32
 #define JANET_WALIGN 4
 #else
 #define JANET_WALIGN 8
 #endif
+#endif
 
 /***** END SECTION CONFIG *****/