Remove default function template argument from the header.
Remove default function template argument from the header.

GCC will treat the default function template arguments as a
compilation error if C++0x is not enabled.

This commit workaround the compilation error by moving the
SFINAE check to function argument instead of the template
argument.


git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@200523 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx