kram - provide hint about installing macOS 15 for avx2 emulation

macOS build apps that can't be updated to universal or arm64 only run x64 emulated portions (even of universal apps).  So important to drop x64 everywhere.

Author: alecazam

kramc/KramMain.cpp

@@ -10,6 +10,7 @@
 
 using namespace STL_NAMESPACE;
 
+// These aren't avx2 specific, but just don't want unused func warning 
 #if SIMD_AVX2
 #if KRAM_MAC
 
@@ -24,6 +25,21 @@ inline const char* getMacOSVersion() {
     return str;
 }
 
+inline bool isRunningUnderRosetta() {
+    int ret = 0;
+    size_t size = sizeof(ret);
+    if (sysctlbyname("sysctl.proc_translated", &ret, &size, NULL, 0) == -1) {
+        if (errno == ENOENT) {
+            // sysctl doesn't exist - not running under Rosetta
+            return false;
+        }
+        // Other error occurred
+        return false;
+    }
+    return ret > 0;
+}
+
+
 inline uint32_t getMacOSMajorVersion() {
     // 15.4
     static uint32_t majorVersion = 0;
@@ -45,10 +61,10 @@ void checkSimdSupport()
 
 #if SIMD_AVX2
 #if KRAM_MAC
-    // Apple added AVX2 support to Rosetta in macOS 15 with no way
+    // Apple added AVX2 and F16C? support to Rosetta in macOS 15 with no way
     // to detect it.   Really awesome, so skip the test.  There are
     // no supporting Intel hw devices on macOS 15 that don't have AVX2.
-    //const char* macOSVersion = getMacOSVersion();
+    // const char* macOSVersion = getMacOSVersion();
     // KLOGI("kram", "%s", macOSVersion);
     uint32_t majorOSVersions = getMacOSMajorVersion();
     if (majorOSVersions >= 15) {
@@ -147,9 +163,12 @@ void checkSimdSupport()
     }
 
     if (!hasSimdSupport) {
-        KLOGE("Main", "Missing simd support for %s%s%s%son %s",
+        bool isEmulated = isRunningUnderRosetta() && (majorVersion < 15);
+        const char* emulatedHint = isEmulated ? " install macOS 15.0+" : "";
+        
+        KLOGE("Main", "Missing simd support for %s%s%s%son %s%s",
               missingFeatures[0], missingFeatures[1], missingFeatures[2], missingFeatures[3],
-              cpuName.data());
+              cpuName.data(), emulatedHint);
         exit(1);
     }