diff --git a/expat/Changes b/expat/Changes
index 56b5aad3..e5f47838 100644
--- a/expat/Changes
+++ b/expat/Changes
@@ -11,9 +11,11 @@ Release x.x.x XXX XXXXXX XX XXXX
             #227  Autotools: Add --without-examples and --without-tests
             #228  Autotools: Modernize configure.ac
             #243  Windows: Fix syntax of .def module definition files
+       #245 #246  Autotools: Fix check for -fvisibility=hidden for Clang
 
         Special thanks to:
             Benjamin Peterson
+            Hanno Böck
             @KangLin
             Marco Maggi
             Sebastian Dröge
diff --git a/expat/conftools/expatcfg-compiler-supports-visibility.m4 b/expat/conftools/expatcfg-compiler-supports-visibility.m4
index 28475180..45d07edf 100644
--- a/expat/conftools/expatcfg-compiler-supports-visibility.m4
+++ b/expat/conftools/expatcfg-compiler-supports-visibility.m4
@@ -27,7 +27,7 @@ AC_DEFUN([EXPATCFG_COMPILER_SUPPORTS_VISIBILITY],
      [expatcfg_cv_compiler_supports_visibility],
      [AS_VAR_SET([expatcfg_cv_compiler_supports_visibility],[no])
       AS_VAR_COPY([OLDFLAGS],[CFLAGS])
-      AS_VAR_APPEND([CFLAGS],[" -fvisibility=hidden -Wall -Werror"])
+      AS_VAR_APPEND([CFLAGS],[" -fvisibility=hidden -Wall -Werror -Wno-unknown-warning-option"])
       AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
           void __attribute__((visibility("default"))) foo(void);
           void foo(void) {}