Add support for loading binary translated DLLs in MinGW

[fwsGonzo]

This is the initial support for loading binary translation DLLs on Windows. #136

$ VERBOSE=1 wine64 rvlinux.exe ../../binaries/stream-rv64gc 
0034:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
0034:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
005c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
005c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
0064:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
0064:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
006c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
006c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
002c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
002c:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
00bc:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
00bc:fixme:font:get_name_record_codepage encoding 20 not handled, platform 1.
* Loading program of size 399580 from 00000000006c7380 to virtual 0000000000010000
* Program segment readable: 1 writable: 0  executable: 1
* Loading program of size 22144 from 00000000007290e0 to virtual 0000000000072d60
* Program segment readable: 1 writable: 1  executable: 0
* Entry is at 0000000000010a50
-------------------------------------------------------------
STREAM version $Revision: 5.10 $
-------------------------------------------------------------
This system uses 8 bytes per array element.
-------------------------------------------------------------
Array size = 10000000 (elements), Offset = 0 (elements)
Memory per array = 76.3 MiB (= 0.1 GiB).
Total memory required = 228.9 MiB (= 0.2 GiB).
Each kernel will be executed 10 times.
 The *best* time for each kernel (excluding the first iteration)
 will be used to compute the reported bandwidth.
-------------------------------------------------------------
Your clock granularity/precision appears to be 1 microseconds.
Each test below will take on the order of 7691 microseconds.
   (= 7691 clock ticks)
Increase the size of the arrays if this shows that
you are not getting at least 20 clock ticks per test.
-------------------------------------------------------------
WARNING -- The above is only a rough guideline.
For best results, please be sure you know the
precision of your system timer.
-------------------------------------------------------------
Function    Best Rate MB/s  Avg time     Min time     Max time
Copy:           25910.9     0.006192     0.006175     0.006210
Scale:          13175.2     0.012379     0.012144     0.012620
Add:            17040.6     0.014267     0.014084     0.014333
Triad:          15944.7     0.015082     0.015052     0.015143
-------------------------------------------------------------
Solution Validates: avg error less than 1.000000e-13 on all three arrays
-------------------------------------------------------------
>>> Program exited, exit code = 0 (0x0)
Instructions executed: 2787575735  Runtime: 530.769ms  Insn/s: 5252mi/s
Pages in use: 110 (440 kB virtual memory, total 1767 kB)

The way it works now is that MachineOptions has settings related to MinGW compilation on Linux (or rather, non-windows) systems where there is an expectation that you have a compiler in PATH.
Constructing options.mingw_options will by default use x86_64-w64-mingw32-gcc as compiler. It will by default produce a rvbintr-HASH.dll in the build folder when a new program is translated.
Using this we can package them with the script programs, load them on-demand, and get a free ~15x increase in performance for the sandboxed code.