2 files changed, 36 insertions, 9 deletions

diff --git a/build-aux/c++defs.h b/build-aux/c++defs.h
index 7d710898..0c2fad7a 100644
--- a/build-aux/c++defs.h
+++ b/build-aux/c++defs.h
@@ -221,10 +221,20 @@
    _GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
 # define _GL_CXXALIASWARN_1(func,namespace) \
    _GL_CXXALIASWARN_2 (func, namespace)
-# define _GL_CXXALIASWARN_2(func,namespace) \
-   _GL_WARN_ON_USE (func, \
-                    "The symbol ::" #func " refers to the system function. " \
-                    "Use " #namespace "::" #func " instead.")
+/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
+   we enable the warning only when not optimizing.  */
+# if !__OPTIMIZE__
+#  define _GL_CXXALIASWARN_2(func,namespace) \
+    _GL_WARN_ON_USE (func, \
+                     "The symbol ::" #func " refers to the system function. " \
+                     "Use " #namespace "::" #func " instead.")
+# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+#  define _GL_CXXALIASWARN_2(func,namespace) \
+     extern __typeof__ (func) func
+# else
+#  define _GL_CXXALIASWARN_2(func,namespace) \
+     _GL_EXTERN_C int _gl_cxxalias_dummy
+# endif
 #else
 # define _GL_CXXALIASWARN(func) \
     _GL_EXTERN_C int _gl_cxxalias_dummy
@@ -239,10 +249,20 @@
                         GNULIB_NAMESPACE)
 # define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
    _GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
-# define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
-   _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
-                        "The symbol ::" #func " refers to the system function. " \
-                        "Use " #namespace "::" #func " instead.")
+/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
+   we enable the warning only when not optimizing.  */
+# if !__OPTIMIZE__
+#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
+    _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
+                         "The symbol ::" #func " refers to the system function. " \
+                         "Use " #namespace "::" #func " instead.")
+# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
+     extern __typeof__ (func) func
+# else
+#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
+     _GL_EXTERN_C int _gl_cxxalias_dummy
+# endif
 #else
 # define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
     _GL_EXTERN_C int _gl_cxxalias_dummy
diff --git a/build-aux/warn-on-use.h b/build-aux/warn-on-use.h
index 1cd5062d..171e5991 100644
--- a/build-aux/warn-on-use.h
+++ b/build-aux/warn-on-use.h
@@ -67,7 +67,10 @@
 /* A compiler attribute is available in gcc versions 4.3.0 and later.  */
 #  define _GL_WARN_ON_USE(function, message) \
 extern __typeof__ (function) function __attribute__ ((__warning__ (message)))
-
+# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+/* Verify the existence of the function.  */
+#  define _GL_WARN_ON_USE(function, message) \
+extern __typeof__ (function) function
 # else /* Unsupported.  */
 #  define _GL_WARN_ON_USE(function, message) \
 _GL_WARN_EXTERN_C int _gl_warn_on_use
@@ -85,6 +88,10 @@ _GL_WARN_EXTERN_C int _gl_warn_on_use
 #  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
 extern rettype function parameters_and_attributes \
      __attribute__ ((__warning__ (msg)))
+# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+/* Verify the existence of the function.  */
+#  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
+extern rettype function parameters_and_attributes
 # else /* Unsupported.  */
 #  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
 _GL_WARN_EXTERN_C int _gl_warn_on_use