Look for orig$ functions from side modules too (emscripten-core#9906)

Fixes emscripten-core#9901

emscripten.py

@@ -1823,10 +1823,11 @@ def create_fp_accessors(metadata):
     accessors.append('''
 Module['%(full)s'] = function() {
   %(assert)s
-  // Use the wasm function itself, for the table.
+  // Use the original wasm function itself, for the table, from the main module.
   var func = Module['asm']['%(original)s'];
-  // If there is no wasm function, this may be a JS library function or
-  // something from another module.
+  // Try an original version from a side module.
+  if (!func) func = Module['_%(original)s'];
+  // Otherwise, look for a regular function or JS library function.
   if (!func) func = Module['%(mangled)s'];
   if (!func) func = %(mangled)s;
   var fp = addFunction(func, '%(sig)s');

tests/test_core.py

@@ -3996,6 +3996,57 @@ def test_dylink_i64_b(self):
       }
     ''', 'other says -1311768467750121224.\nmy fp says: 43.\nmy second fp says: 43.')
 
+  @needs_dlfcn
+  def test_dylink_i64_c(self):
+    self.dylink_test(r'''
+      #include <cstdio>
+      #include <cinttypes>
+      #include "header.h"
+
+      typedef int32_t (*fp_type_32)(int32_t, int32_t, int32_t);
+      typedef int64_t (*fp_type_64)(int32_t, int32_t, int32_t);
+
+      int32_t internal_function_ret_32(int32_t i, int32_t j, int32_t k) {
+          return 32;
+      }
+      int64_t internal_function_ret_64(int32_t i, int32_t j, int32_t k) {
+          return 64;
+      }
+
+      int main() {
+          fp_type_32 fp32_internal = &internal_function_ret_32;
+          fp_type_32 fp32_external = &function_ret_32;
+          fp_type_64 fp64_external = &function_ret_64;
+          fp_type_64 fp64_internal = &internal_function_ret_64;
+          int32_t ires32 = fp32_internal(0,0,0);
+          printf("res32 - internal %d\n",ires32);
+          int32_t eres32 = fp32_external(0,0,0);
+          printf("res32 - external %d\n",eres32);
+
+          int64_t ires64 = fp64_internal(0,0,0);
+          printf("res64 - internal %" PRId64 "\n",ires64);
+          int64_t eres64 = fp64_external(0,0,0);
+          printf("res64 - external %" PRId64 "\n",eres64);
+          return 0;
+      }
+    ''', '''
+      #include "header.h"
+      int32_t function_ret_32(int32_t i, int32_t j, int32_t k) {
+          return 32;
+      }
+      int64_t function_ret_64(int32_t i, int32_t j, int32_t k) {
+          return 64;
+      }
+    ''', '''res32 - internal 32
+res32 - external 32
+res64 - internal 64
+res64 - external 64\n''', header='''
+      #include <emscripten.h>
+      #include <cstdint>
+      EMSCRIPTEN_KEEPALIVE int32_t function_ret_32(int32_t i, int32_t j, int32_t k);
+      EMSCRIPTEN_KEEPALIVE int64_t function_ret_64(int32_t i, int32_t j, int32_t k);
+    ''')
+
   @needs_dlfcn
   def test_dylink_class(self):
     self.dylink_test(header=r'''