new file mode 100644
--- /dev/null
+++ b/extensions/spellcheck/hunspell/patches/bug1838113.patch
@@ -0,0 +1,20 @@
+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();
--- a/extensions/spellcheck/hunspell/src/csutil.cxx
+++ b/extensions/spellcheck/hunspell/src/csutil.cxx
@@ -103,16 +103,17 @@ struct unicode_info2 {
   unsigned short cupper;
   unsigned short clower;
 };
 
 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)
 #define WIN32_LONG_PATH_PREFIX "\\\\?\\"
   if (strncmp(path, WIN32_LONG_PATH_PREFIX, 4) == 0) {
     int len = MultiByteToWideChar(CP_UTF8, 0, path, -1, NULL, 0);
     wchar_t* buff = new wchar_t[len];
     wchar_t* buff2 = new wchar_t[len];
@@ -122,16 +123,17 @@ void myopen(std::ifstream& stream, const
     }
     delete [] buff;
     delete [] buff2;
   }
   else
 #endif
   stream.open(path, mode);
 }
+#endif
 
 std::string& u16_u8(std::string& dest, const std::vector<w_char>& src) {
   dest.clear();
   std::vector<w_char>::const_iterator u2 = src.begin();
   std::vector<w_char>::const_iterator u2_max = src.end();
   while (u2 < u2_max) {
     signed char u8;
     if (u2->h) {  // > 0xFF
--- a/extensions/spellcheck/hunspell/update.sh
+++ b/extensions/spellcheck/hunspell/update.sh
@@ -29,3 +29,4 @@ rm -rf ${tmpclonedir}
 cd ${hunspell_dir}/src
 patch -p5 < ../patches/bug1410214.patch
 patch -p5 < ../patches/bug1739761.patch
+patch -p5 < ../patches/bug1838113.patch