Fix checking for round()

Old check fails on current GCC/glibc with
"error: statement cannot resolve address of overloaded function"

configure

@@ -30801,68 +30801,36 @@ _ACEOF
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for round" >&5
+$as_echo_n "checking for round... " >&6; }
+if ${wx_cv_func_round+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
 ac_ext=cpp
 ac_cpp='$CXXCPP $CPPFLAGS'
 ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
-
-  for wx_func in round
-  do
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $wx_func" >&5
-$as_echo_n "checking for $wx_func... " >&6; }
-if eval \${wx_cv_func_$wx_func+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-
-        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-
-
-                #include <math.h>
-                $ac_includes_default
-
+#include <math.h>
 int
 main ()
 {
-
-                #ifndef $wx_func
-                  &$wx_func;
-                #endif
-
-
+return int(round(0.0))
   ;
   return 0;
 }
-
 _ACEOF
 if ac_fn_cxx_try_link "$LINENO"; then :
-  eval wx_cv_func_$wx_func=yes
+  wx_cv_func_round=yes
 else
-  eval wx_cv_func_$wx_func=no
+  wx_cv_func_round=no
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
-
-fi
-eval ac_res=\$wx_cv_func_$wx_func
-	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-$as_echo "$ac_res" >&6; }
-
-    if eval test \$wx_cv_func_$wx_func = yes
-    then
-      cat >>confdefs.h <<_ACEOF
-#define `$as_echo "HAVE_$wx_func" | $as_tr_cpp` 1
-_ACEOF
-
-
-    else
-      :
-
-    fi
-  done
-
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -30870,6 +30838,14 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $wx_cv_func_round" >&5
+$as_echo "$wx_cv_func_round" >&6; }
+if test "$wx_cv_func_round" = yes; then
+    $as_echo "#define HAVE_ROUND 1" >>confdefs.h
+
+fi
+
 if test "$TOOLKIT" != "MSW"; then
 
 if test "$wxUSE_LIBICONV" != "no" ; then

configure.in

@@ -4193,9 +4193,17 @@ fi
 
 dnl at least under IRIX with mipsPro the C99 round() function is available when
 dnl building using the C compiler but not when using C++ one
+AC_CACHE_CHECK([for round], wx_cv_func_round, [
 AC_LANG_PUSH(C++)
-WX_CHECK_FUNCS(round,,,[#include <math.h>])
+AC_TRY_LINK(
+    [#include <math.h>],
+    [return int(round(0.0))],
+    wx_cv_func_round=yes, wx_cv_func_round=no)
 AC_LANG_POP()
+])
+if test "$wx_cv_func_round" = yes; then
+    AC_DEFINE(HAVE_ROUND)
+fi
 
 dnl the following tests are for Unix(like) systems only
 if test "$TOOLKIT" != "MSW"; then