Fix -Woverloaded-virtual warnings in ICU.

source/i18n/winnmfmt.cpp

Index: source/i18n/winnmfmt.cpp
diff --git a/source/i18n/winnmfmt.cpp b/source/i18n/winnmfmt.cpp
index 58e2a497b194bc281a817d9ced39372efab0bfee..d5ea8bde07acea3c0fa3b48aa63c07e054fecbc1 100644
--- a/source/i18n/winnmfmt.cpp
+++ b/source/i18n/winnmfmt.cpp
@@ -209,17 +209,17 @@ Format *Win32NumberFormat::clone(void) const
 
 UnicodeString& Win32NumberFormat::format(double number, UnicodeString& appendTo, FieldPosition& pos) const
 {
-    return format(getMaximumFractionDigits(), appendTo, L"%.16f", number);
+    return variadicFormat(getMaximumFractionDigits(), appendTo, L"%.16f", number);
 }
 
 UnicodeString& Win32NumberFormat::format(int32_t number, UnicodeString& appendTo, FieldPosition& pos) const
 {
-    return format(getMinimumFractionDigits(), appendTo, L"%I32d", number);
+    return variadicFormat(getMinimumFractionDigits(), appendTo, L"%I32d", number);
 }
 
 UnicodeString& Win32NumberFormat::format(int64_t number, UnicodeString& appendTo, FieldPosition& pos) const
 {
-    return format(getMinimumFractionDigits(), appendTo, L"%I64d", number);
+    return variadicFormat(getMinimumFractionDigits(), appendTo, L"%I64d", number);
 }
 
 void Win32NumberFormat::parse(const UnicodeString& text, Formattable& result, ParsePosition& parsePosition) const
@@ -242,7 +242,7 @@ void Win32NumberFormat::setMinimumFractionDigits(int32_t newValue)
     NumberFormat::setMinimumFractionDigits(newValue);
 }
 
-UnicodeString &Win32NumberFormat::format(int32_t numDigits, UnicodeString &appendTo, const wchar_t *fmt, ...) const
+UnicodeString &Win32NumberFormat::variadicFormat(int32_t numDigits, UnicodeString &appendTo, const wchar_t *fmt, ...) const
 {
     wchar_t nStackBuffer[STACK_BUFFER_SIZE];
     wchar_t *nBuffer = nStackBuffer;