parseNumberFromString cannot parse floating point numbers with hex base specifiers on Solaris and Windows

See https://github.com/mongodb/mongo/blob/r2.7.1/src/mongo/base/parse_number_test.cpp#L300

The issue is that the system libraries that parseNumberFromString uses do not correctly parse these values. For example: "0x10.1" is not parseable on these platforms.

User visible impact:

• command line parsing
• JSON parsing
• other?