clang now issuing depreciation warnings on use of sprintf

[mclow]

In file included from ./boost/test/output/compiler_log_formatter.hpp:19:
./boost/test/utils/setcolor.hpp:92:31: warning: 'sprintf' is deprecated: This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead. [-Wdeprecated-declarations]
        m_command_size = std::sprintf( m_control_command, "%c[%c;3%c;4%cm",
                              ^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdio.h:188:1: note: 'sprintf' has been explicitly marked deprecated here
__deprecated_msg("This function is provided for compatibility reasons only.  Due to security concerns inherent in the design of sprintf(3), it is highly recommended that you use snprintf(3) instead.")
^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:215:48: note: expanded from macro '__deprecated_msg'
        #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
                                                      ^

The good news is that the change is really easy

- m_command_size = std::sprintf(  m_control_command,                            "%c[%c;3%c;4%cm",
+ m_command_size = std::snprintf( m_control_command, sizeof(m_control_command), "%c[%c;3%c;4%cm",

since m_control_command is a statically-sized array of char.