Move WASMFS C++ link hack to emcc.py (#15179)

This way WasmFS can be used outside the test suite as well.

Followup to #15147

Author: kripken

emcc.py

@@ -2330,6 +2330,10 @@ def get_full_import_name(name):
 
   settings.LINK_AS_CXX = (run_via_emxx or settings.DEFAULT_TO_CXX) and '-nostdlib++' not in newargs
 
+  # WASMFS itself is written in C++, and needs C++ standard libraries
+  if settings.WASMFS:
+    settings.LINK_AS_CXX = True
+
   return target, wasm_target
 
 

tests/common.py

@@ -551,7 +551,7 @@ def verify_es5(self, filename):
   def build(self, filename, libraries=[], includes=[], force_c=False, js_outfile=True, emcc_args=[], output_basename=None):
     suffix = '.js' if js_outfile else '.wasm'
     compiler = [compiler_for(filename, force_c)]
-    if compiler[0] == EMCC and not self.get_setting('WASMFS'):
+    if compiler[0] == EMCC:
       # TODO change test behaviour in the future when WASMFS becomes default file system
       # WASMFS is excluded here since it currently requires stdlib++ functions
       # TODO(https://github.com/emscripten-core/emscripten/issues/11121)