2008-10-27  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/37522
	* config/os/mingw32/os_defines.h: Define _GLIBCXX_HAVE_BROKEN_VSWPRINTF
	* include/bits/basic_string.h: Guard string conversions with 
	!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) too.
	* testsuite/lib/libstdc++.exp (check_v3_target_string_conversions):
	New.
	* testsuite/lib/dg-options.exp (dg-require-string-conversions): New.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stof.cc:
	Use the latter.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stoll.cc:
	Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stoi.cc:
	Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stol.cc:
	Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/
	stoull.cc: Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stold.cc:
	Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stoul.cc:
	Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/
	to_string.cc: Likewise.
	* testsuite/21_strings/basic_string/numeric_conversions/char/stod.cc:
	Likewise.