This reverts commit 1c58876185d2a4ed87dac4a54b82f607e74f55fd.
std::snprintf() is only available in C++11, which is not provided by
all compilers. Since the C library snprintf() can easily be used as a
replacement on Linux systems, this patch changes jsoncpp to use the C
library snprintf() instead of C++11 std::snprintf(), fixing the build error
below:
src/lib_json/json_writer.cpp:33:18: error: 'snprintf' is not a member of 'std'
See #231, #224, and #218.