automatically check for floating-point instrs in DR code at build time

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on May 26, 2011 11:44:18_

xref issue #386 DynamoRIO assumes that its code does not affect floating-point state. In
the past we've had cases where cl (the VS compiler) will use floating-point
instructions where we don't expect them ( issue #386 ). I don't think there's any
flag or pragma to prevent this, but at the least we'd like to detect it.

"dumpbin /disasm" produces a bunch of non-code disassembly so it requires
some manual examination to decide what apparent fp instrs are really data
or padding between functions. I was using scripts to grep for opcodes
starting with f and manually examining the results. to automate we'd want
to query symbols and disassemble down to the ret (assuming there's only one
and it's at the end) and assume the rest of the bytes still labeled as that
symbol are padding.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=468_