Figure out the exact set of compiler flags used to produce Diablo.exe (1.09b)

This issue tracks the effort to figure out the complier flags used to produce Diablo.exe (version 1.09b). It may be considered a subtask of #11, as given information about compiler flags, we can ensure that the same input source code produce the same output object code.

From what I can tell, it seems like `/O1` is used rather than `/O2`. This is based on the padding between functions.

`/O2` produces (given that https://github.com/diasurgical/devilution/pull/110 has been merged):

```asm
401000: e9 0b 00 00 00 jmp 0x401010
401005: 90 nop
401006: 90 nop
401007: 90 nop
401008: 90 nop
401009: 90 nop
40100a: 90 nop
40100b: 90 nop
40100c: 90 nop
40100d: 90 nop
40100e: 90 nop
40100f: 90 nop
401010: a1 28 b1 40 00 mov eax,ds:0x40b128
401015: a3 84 1a 41 00 mov ds:0x411a84,eax
40101a: c3 ret
40101b: 90 nop
40101c: 90 nop
40101d: 90 nop
40101e: 90 nop
40101f: 90 nop
401020: 8b 44 24 04 mov eax,DWORD PTR [esp+0x4]
401024: 85 c0 test eax,eax
401026: 74 0f je 0x401037
401028: 6a 00 push 0x0
40102a: 6a ff push 0xffffffff
40102c: 68 40 d0 40 00 push 0x40d040
401031: 50 push eax
401032: e8 69 0c 00 00 call 0x401ca0
401037: c3 ret
```

While `/O1` produces:

```asm
401000: e9 00 00 00 00 jmp 0x401005
401005: a1 28 c1 40 00 mov eax,ds:0x40c128
40100a: a3 84 2a 41 00 mov ds:0x412a84,eax
40100f: c3 ret
401010: 83 7c 24 04 00 cmp DWORD PTR [esp+0x4],0x0
401015: 74 12 je 0x401029
401017: 6a 00 push 0x0
401019: 6a ff push 0xffffffff
40101b: 68 40 e0 40 00 push 0x40e040
401020: ff 74 24 10 push DWORD PTR [esp+0x10]
401024: e8 8f 09 00 00 call 0x4019b8
401029: c3 ret
```

This is to be compared to the original version of Diablo.exe (1.09b):

```asm
401000: e9 00 00 00 00 jmp 0x401005
401005: a1 00 94 47 00 mov eax,ds:0x479400
40100a: a3 30 79 4b 00 mov ds:0x4b7930,eax
40100f: c3 ret
401010: 83 7c 24 04 00 cmp DWORD PTR [esp+0x4],0x0
401015: 74 12 je 0x401029
401017: 6a 00 push 0x0
401019: 6a ff push 0xffffffff
40101b: 68 b0 30 48 00 push 0x4830b0
401020: ff 74 24 10 push DWORD PTR [esp+0x10]
401024: e8 8d 87 06 00 call 0x4697b6
401029: c3 ret
```