fix(cpu_features): refactor architecture detection to explicit x86 whitelist

Currently, `cpu_features.cc` assumes any non-ARM architecture is x86/x64, which leads to a fatal missing `<cpuid.h>` error on architectures like RISC-V.
This commit refactors the preprocessor macros to explicitly whitelist x86 architectures (`__x86_64__`, `__i386__`, `_M_X64`, `_M_IX86`). All other architectures (RISC-V, ARM, etc.) will now safely fall back to the default zero-initialization, allowing cross-compilation to succeed.

Signed-off-by: ihb2032 <hebome@foxmail.com>

Author: ihb2032

src/ailego/internal/cpu_features.cc

@@ -17,7 +17,9 @@
 
 #if defined(_MSC_VER)
 #include <intrin.h>
-#elif !defined(__ARM_ARCH)
+#endif
+
+#if (defined(__x86_64__) || defined(__i386__)) && !defined(_MSC_VER)
 #include <cpuid.h>
 #endif
 
@@ -34,7 +36,7 @@ namespace internal {
 
 CpuFeatures::CpuFlags CpuFeatures::flags_;
 
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86))
 CpuFeatures::CpuFlags::CpuFlags(void)
     : L1_ECX(0), L1_EDX(0), L7_EBX(0), L7_ECX(0), L7_EDX(0) {
   int l1[4] = {0, 0, 0, 0};
@@ -48,7 +50,7 @@ CpuFeatures::CpuFlags::CpuFlags(void)
   L7_ECX = l7[2];
   L7_EDX = l7[3];
 }
-#elif !defined(__ARM_ARCH)
+#elif defined(__x86_64__) || defined(__i386__)
 CpuFeatures::CpuFlags::CpuFlags(void)
     : L1_ECX(0), L1_EDX(0), L7_EBX(0), L7_ECX(0), L7_EDX(0) {
   uint32_t eax, ebx, ecx, edx;