close #19 : add cmake option for single-file wasm build

If enabled, we build ggwave using "-s SINGLE_FILE=1" which causes
the WASM to be embedded inside the .js file.

Otherwise, 2 separate files are produced:
- libggwave.js
- libggwave.wasm

CMakeLists.txt

@@ -21,6 +21,8 @@ endif()
 if (EMSCRIPTEN)
     set(GGWAVE_SUPPORT_SDL2_DEFAULT ON)
     set(BUILD_SHARED_LIBS_DEFAULT OFF)
+
+    option(GGWAVE_WASM_SINGLE_FILE "ggwave: embed WASM inside the generated ggwave.js" ON)
 else()
     set(GGWAVE_SUPPORT_SDL2_DEFAULT ON)
     set(BUILD_SHARED_LIBS_DEFAULT ON)

bindings/javascript/CMakeLists.txt

@@ -8,17 +8,23 @@ target_link_libraries(${TARGET} PRIVATE
     ggwave
     )
 
+unset(EXTRA_FLAGS)
+if (GGWAVE_WASM_SINGLE_FILE)
+    set(EXTRA_FLAGS "-s SINGLE_FILE=1")
+    message(STATUS "Embedding WASM inside ggwave.js")
+
+    add_custom_command(
+        TARGET libggwave POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+        ${CMAKE_BINARY_DIR}/bin/libggwave.js
+        ${CMAKE_CURRENT_SOURCE_DIR}/ggwave.js
+        )
+endif()
+
 set_target_properties(${TARGET} PROPERTIES LINK_FLAGS " \
     --bind \
     -s MODULARIZE=1 \
-    -s SINGLE_FILE=1 \
     -s ALLOW_MEMORY_GROWTH=1 \
     -s EXPORT_NAME=\"'ggwave_factory'\" \
+    ${EXTRA_FLAGS} \
     ")
-
-add_custom_command(
-    TARGET libggwave POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy
-    ${CMAKE_BINARY_DIR}/bin/libggwave.js
-    ${CMAKE_CURRENT_SOURCE_DIR}/ggwave.js
-    )