The `std::bitflags::bitflags!` macro did not provide support for
adding attributes to the generated structure or flags, due to
limitations in the parser for macros. This patch works around the
parser limitations by requiring a `flags` keyword in the overall
`bitflags!` invocation, and a `static` keyword for each flag:
bitflags!(
#[deriving(Hash)]
#[doc="Three flags"]
flags Flags: u32 {
#[doc="The first flag"]
static FlagA = 0x00000001,
static FlagB = 0x00000010,
static FlagC = 0x00000100
}
)
