[Web] Add emscripten_include_path option

Author: adamscott

platform/web/detect.py

@@ -41,6 +41,7 @@ def get_opts():
         # Matches default values from before Emscripten 3.1.27. New defaults are too low for Godot.
         ("stack_size", "WASM stack size (in KiB)", 5120),
         ("default_pthread_stack_size", "WASM pthread default stack size (in KiB)", 2048),
+        ("emscripten_include_path", "Emscripten include/ path", ""),
         BoolVariable("use_assertions", "Use Emscripten runtime assertions", False),
         BoolVariable("use_ubsan", "Use Emscripten undefined behavior sanitizer (UBSAN)", False),
         BoolVariable("use_asan", "Use Emscripten address sanitizer (ASAN)", False),
@@ -110,6 +111,10 @@ def configure(env: "SConsEnvironment"):
         print_error("Initial memory must be a valid integer")
         sys.exit(255)
 
+    ## Emscripten setup
+    if env["emscripten_include_path"]:
+        env.Append(CPPPATH=[env["emscripten_include_path"]])
+
     ## Build type
 
     if env.debug_features: