diff --git a/extensions/spellcheck/hunspell/src/csutil.cxx b/extensions/spellcheck/hunspell/src/csutil.cxx
index 48e58ff4b2677..39a54d38023c8 100644
--- a/extensions/spellcheck/hunspell/src/csutil.cxx
+++ b/extensions/spellcheck/hunspell/src/csutil.cxx
@@ -108,6 +108,7 @@ static struct unicode_info2* utf_tbl = NULL;
 static int utf_tbl_count =
     0;  // utf_tbl can be used by multiple Hunspell instances
 
+#ifndef MOZILLA_CLIENT
 void myopen(std::ifstream& stream, const char* path, std::ios_base::openmode mode)
 {
 #if defined(_WIN32) && defined(_MSC_VER)
@@ -127,6 +128,7 @@ void myopen(std::ifstream& stream, const char* path, std::ios_base::openmode mod
 #endif
   stream.open(path, mode);
 }
+#endif
 
 std::string& u16_u8(std::string& dest, const std::vector<w_char>& src) {
   dest.clear();