diff --git a/GNUmakefile b/GNUmakefile
index e7501c0f..4f4cb21d 100755
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -30,16 +30,16 @@ else
   GREP ?= grep
 endif
 
-IS_X86 := $(shell uname -m | $(GREP) -v "64" | $(GREP) -i -c -E "i.86|x86|i86")
-IS_X64 := $(shell uname -m | $(GREP) -i -c -E "(_64|d64)")
-IS_PPC32 := $(shell uname -m | $(GREP) -i -v "64" | $(GREP) -i -c -E "ppc|power")
-IS_PPC64 := $(shell uname -m | $(GREP) -i -c -E "ppc64|power64")
-IS_ARM32 := $(shell uname -m | $(GREP) -i -v "64" | $(GREP) -i -c -E 'armhf|arm7l|eabihf')
-IS_ARM64 := $(shell uname -m | $(GREP) -i -c 'aarch64')
-IS_ARMV8 ?= $(shell uname -m | $(GREP) -i -c -E 'aarch32|aarch64')
-IS_NEON ?= $(shell uname -m | $(GREP) -i -c -E 'armv7|armv8|aarch32|aarch64')
-IS_SPARC := $(shell uname -m | $(GREP) -i -c "sparc")
-IS_SPARC64 := $(shell uname -m | $(GREP) -i -c "sparc64")
+IS_X86 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -v "64" | $(GREP) -i -c -E "i.86|x86|i86")
+IS_X64 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c -E "(_64|d64)")
+IS_PPC32 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -v "64" | $(GREP) -i -c -E "ppc|power")
+IS_PPC64 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c -E "ppc64|power64")
+IS_ARM32 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -v "64" | $(GREP) -i -c -E 'armhf|arm7l|eabihf')
+IS_ARM64 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c 'aarch64')
+IS_ARMV8 ?= $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c -E 'aarch32|aarch64')
+IS_NEON ?= $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c -E 'armv7|armv8|aarch32|aarch64')
+IS_SPARC := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c "sparc")
+IS_SPARC64 := $(shell $(CXX) $(CXXFLAGS) -dumpmachine 2>/dev/null | $(GREP) -i -c "sparc64")
 
 IS_AIX := $(shell uname -s | $(GREP) -i -c 'aix')
 IS_SUN := $(shell uname -s | $(GREP) -i -c "SunOS")
diff --git a/cpu.cpp b/cpu.cpp
index ed341e60..a354ed9f 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -54,6 +54,15 @@ NAMESPACE_BEGIN(CryptoPP)
 extern "C" {
     typedef void (*SigHandler)(int);
 };
+
+extern "C"
+{
+	static jmp_buf s_jmpNoCPUID;
+	static void SigIllHandlerCPUID(int)
+	{
+		longjmp(s_jmpNoCPUID, 1);
+	}
+}
 #endif  // Not CRYPTOPP_MS_STYLE_INLINE_ASSEMBLY
 
 // *************************** IA-32 CPUs ***************************
@@ -83,17 +92,6 @@ inline bool CpuId(word32 func, word32 subfunc, word32 output[4])
 
 #else
 
-#ifndef CRYPTOPP_MS_STYLE_INLINE_ASSEMBLY
-extern "C"
-{
-	static jmp_buf s_jmpNoCPUID;
-	static void SigIllHandlerCPUID(int)
-	{
-		longjmp(s_jmpNoCPUID, 1);
-	}
-}
-#endif
-
 // Borland/Embarcadero and Issue 498
 // cpu.cpp (131): E2211 Inline assembly not allowed in inline and template functions
 bool CpuId(word32 func, word32 subfunc, word32 output[4])
@@ -297,7 +295,7 @@ void DetectX86Features()
 	if (!g_cacheLineSize)
 		g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;
 
-	g_x86DetectionDone = true;
+	*const_cast<volatile bool*>(&g_x86DetectionDone) = true;
 }
 
 // *************************** ARM-32, Aarch32 and Aarch64 ***************************
@@ -561,7 +559,7 @@ void DetectArmFeatures()
 	if (!g_cacheLineSize)
 		g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;
 
-	g_ArmDetectionDone = true;
+	*const_cast<volatile bool*>(&g_ArmDetectionDone) = true;
 }
 
 // *************************** PowerPC and PowerPC64 ***************************
@@ -683,7 +681,7 @@ void DetectPowerpcFeatures()
 	if (g_cacheLineSize <= 0)
 		g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;
 
-	g_PowerpcDetectionDone = true;
+	*const_cast<volatile bool*>(&g_PowerpcDetectionDone) = true;
 }
 
 #endif
diff --git a/sse-simd.cpp b/sse-simd.cpp
index 192066d7..0bad4a48 100644
--- a/sse-simd.cpp
+++ b/sse-simd.cpp
@@ -42,7 +42,9 @@ extern "C"
 
 bool CPU_ProbeSSE2()
 {
-#if CRYPTOPP_BOOL_X64
+	// Apple switched to Intel desktops in 2005/2006 using
+	//   Core2 Duo's, which provides SSE2 and above.
+#if CRYPTOPP_BOOL_X64 || defined(__APPLE__)
 	return true;
 #elif defined(CRYPTOPP_NO_CPU_FEATURE_PROBES)
 	return false;