From:
http://buildroot.uclibc.org/cgi-bin/viewcvs.cgi/*checkout*/trunk/buildroot/toolchain/gcc/4.0.2/302-c99-snprintf.patch?rev=11715

--- gcc-4.0.0/libstdc++-v3/include/c_std/std_cstdio.h-orig	2005-04-29 00:08:41.000000000 -0500
+++ gcc-4.0.0/libstdc++-v3/include/c_std/std_cstdio.h	2005-04-29 00:08:45.000000000 -0500
@@ -142,7 +142,7 @@
   using ::vsprintf;
 }
 
-#if _GLIBCXX_USE_C99
+#if _GLIBCXX_USE_C99 || defined(__UCLIBC__)
 
 #undef snprintf
 #undef vfscanf