Fix Windows CI: MSVC __builtin_* shims, pthread_create/join, M_PI, timespec

- tq_gguf_quants.c: shim __builtin_prefetch and __builtin_return_address
- tq_moe.c: shim __builtin_prefetch for MSVC
- tq_ops.c: add pthread_create/join/cond_signal via _beginthreadex
- test_neon_scalar.cpp: define _USE_MATH_DEFINES before cmath for M_PI
- tools/quant.c: skip timespec redefinition on MSVC >= 2015

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: unamedkr

src/engine/tq_gguf_quants.c

@@ -24,6 +24,12 @@
 #define TQ_HAS_NEON 0
 #endif
 
+/* MSVC: no __builtin_* intrinsics */
+#ifdef _MSC_VER
+#define __builtin_prefetch(addr, ...) ((void)0)
+#define __builtin_return_address(n) ((void*)0)
+#endif
+
 /* ============================================================
  * FP16 / BF16 helpers
  * ============================================================ */

src/engine/tq_moe.c

@@ -22,6 +22,10 @@
 #define TQ_MOE_HAS_NEON 0
 #endif
 
+#ifdef _MSC_VER
+#define __builtin_prefetch(addr, ...) ((void)0)
+#endif
+
 #ifdef TQ_HAS_ACCELERATE
 #include <Accelerate/Accelerate.h>
 #endif

src/engine/tq_ops.c

@@ -41,6 +41,15 @@ typedef SRWLOCK pthread_mutex_srw_t;
 #undef pthread_mutex_destroy
 #define pthread_mutex_destroy(m) ((void)0)
 #define PTHREAD_MUTEX_INITIALIZER SRWLOCK_INIT
+#define pthread_cond_signal(c) WakeConditionVariable(c)
+#include <process.h>
+static inline int pthread_create(pthread_t* t, const void* a, void*(*fn)(void*), void* arg) {
+    (void)a; *t = (HANDLE)_beginthreadex(NULL,0,(unsigned(__stdcall*)(void*))fn,arg,0,NULL);
+    return *t ? 0 : -1;
+}
+static inline int pthread_join(pthread_t t, void** r) {
+    (void)r; WaitForSingleObject(t, INFINITE); CloseHandle(t); return 0;
+}
 #else
 #include <pthread.h>
 #endif

tests/test_neon_scalar.cpp

@@ -13,6 +13,9 @@
  * - uniform_4b quantize/dequantize: KV cache uniform quantization
  */
 
+#ifdef _MSC_VER
+#define _USE_MATH_DEFINES
+#endif
 #include <gtest/gtest.h>
 #include <cmath>
 #include <vector>

tools/quant.c

@@ -43,7 +43,7 @@
 #ifndef CLOCK_MONOTONIC
 #define CLOCK_MONOTONIC 1
 #endif
-#if defined(_WIN32) && !defined(_TIMESPEC_DEFINED) && !defined(__struct_timespec_defined)
+#if defined(_WIN32) && !defined(_TIMESPEC_DEFINED) && !defined(__struct_timespec_defined) && (!defined(_MSC_VER) || _MSC_VER < 1900)
 #define _TIMESPEC_DEFINED 1
 #define __struct_timespec_defined 1
 struct timespec { long tv_sec; long tv_nsec; };