Fixed conformance warnings based on clang

[walbourn]

Fixed some warnings

• old-style-casts
• zero-as-null-pointer-constant
• undefined reinterpret-cast behavior
• sign-conversion
• sign-shift-overflow
• extra-semi

[walbourn]

To get a 'clean build' you'll need to suppress a bunch of stuff that is likely an issue throughout your codebase:

#pragma clang diagnostic ignored "-Wc++98-compat"
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
#pragma clang diagnostic ignored "-Wfloat-equal"
#pragma clang diagnostic ignored "-Wgnu-anonymous-struct"
#pragma clang diagnostic ignored "-Wmissing-variable-declarations"
#pragma clang diagnostic ignored "-Wnested-anon-types"
#pragma clang diagnostic ignored "-Wnonportable-include-path"
#pragma clang diagnostic ignored "-Wnonportable-system-include-path"
#pragma clang diagnostic ignored "-Wreserved-id-macro"
#pragma clang diagnostic ignored "-Wundef"