Add API stubs for Go binary emulation

[williballenthin]

Summary

• Add winmm.dll and bcryptprimitives.dll to the default module config so the Go runtime can load them via LoadLibraryExW
• Add bcryptprimitives.ProcessPrng stub (Go 1.20+ requires this for CSPRNG)
• Add kernel32 stubs: AddVectoredContinueHandler, CreateWaitableTimerExW, GetProcessAffinityMask, SetConsoleCtrlHandler, GetErrorMode, WerGetFlags, WerSetFlags
• Add ntdll stubs: RtlGetNtVersionNumbers, RtlGetCurrentPeb, RtlGetVersion
• Add winmm stubs: timeBeginPeriod, timeEndPeriod

Closes #223

Before

Go binaries crash immediately with unsupported_api after ~7 API calls during runtime initialization.

After

Go runtime initializes fully — loads libraries, allocates heap, spawns threads, reads environment (188+ API calls). The runtime still panics (exit code 2) due to deeper emulation gaps (thread scheduling, std handle initialization), but the unsupported_api crashes are resolved.

Test plan

• Existing test suite passes (50 pass, 13 skipped — unchanged)
• Ruff lint passes on all changed files
• Verified with cross-compiled Go 1.25 hello world binary (GOOS=windows GOARCH=amd64)

🤖 Generated with Claude Code

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[williballenthin]

Investigation: What it takes to fully emulate Go binaries

After getting the initial API stubs in place, "I" (read: Opus) did a deeper investigation into what's needed for a Go hello-world to actually print output. Here's the full picture.

Root cause chain

1. fatal error: nanotime returning zero — Go reads time directly from KUSER_SHARED_DATA (0x7FFE0000) without calling QueryPerformanceCounter. Speakeasy mapped this page but left it zero-filled. Fixed in latest push — populated with QpcFrequency, InterruptTime, SystemTime, etc.

2. GetStdHandle returns 0 on amd64 — The STD_ERROR_HANDLE constant 0xFFFFFFF4 (32-bit DWORD) doesn't match 0xFFFFFFFFFFFFFFF4 (64-bit sign-extended value from RCX). Fixed — added dev & 0xFFFFFFFF mask in get_std_handle().

3. fatal error: stoplockedm: not runnable — Go's M:N scheduler requires concurrent thread execution. The sysmon thread (created via CreateThread) must run simultaneously with the main goroutine. Not fixable with stubs — this is an architectural limitation of speakeasy's execution model. See also CreateThread and WaitForXXX APi #86

Thread model analysis

Speakeasy's start() loop (winemu.py:507-571) breaks after the first run completes successfully. Created threads are queued in run_queue but only execute if the primary run raises an exception. Go's sysmon thread never gets CPU time, so the scheduler enters an invalid state when the main goroutine tries to yield.

Two potential approaches to fix this (both non-trivial):

• Run-queue draining: After ExitProcess, continue executing queued thread runs. Simple but insufficient — Go needs threads concurrent with main, not sequential after it.
• Cooperative scheduling: On blocking APIs (WaitForSingleObject, Sleep, SwitchToThread), save thread state and switch to the next queued run. This could work for Go but requires significant changes to the core emulation loop.

Other findings

Area	Status
TlsAlloc returns index 0	Not a problem — Go checks against TLS_OUT_OF_INDEXES
VirtualQuery on reserved memory	Returns ERROR_INVALID_PARAMETER (only committed regions are visible). Secondary issue — not the current crash point
powrprof.dll missing	Go handles gracefully
KUSER_SHARED_DATA unpopulated	Fixed
GetStdHandle 32/64-bit mismatch	Fixed

Current state

With all three commits, Go runtime initialization proceeds through: library loading → heap allocation (including 0xC000000000 region) → thread creation → environment loading → 627+ API calls. The runtime reaches the goroutine scheduler before hitting the threading wall.

[williballenthin]

lgtm

[mr-tz]

very very nice, just one minor question