Crypto: fix NOASM link failures on x86 (#1896)

With NOASM=1 on x86/x64 the assembler module Aes_hw_cpu is not built,
but cpu.h still defines TC_AES_HW_CPU, so Cipher.cpp references
aes_hw_cpu_encrypt/decrypt. cpu.c also still declares and calls
TrySHA256, which Sha2Intel.c omits when CRYPTOPP_DISABLE_ASM is set
(NOASM passes CRYPTOPP_DISABLE_X86ASM, which implies it), and this
happens whenever __SHA__ is defined (-msha, -march=native) or
CRYPTOPP_SHANI_AVAILABLE is set.

- cpu.h: define TC_AES_HW_CPU on x86 only without CRYPTOPP_DISABLE_ASM
- cpu.c: declare and call TrySHA256 only under the same condition
  Sha2Intel.c uses to build it (not _UEFI, not CRYPTOPP_DISABLE_ASM)

Both follow the compiler target, so cross builds need no ARCH override.

Signed-off-by: Ville Takio <ville+git@takio.fi>

src/Crypto/cpu.c

@@ -290,7 +290,10 @@ static int Detect_MS_HyperV_AES ()
 
 #endif
 
-#if defined(__SHA__) || defined(__INTEL_COMPILER) || CRYPTOPP_SHANI_AVAILABLE
+/* TrySHA256 lives in Sha2Intel.c, which omits it for _UEFI and CRYPTOPP_DISABLE_ASM */
+#if !defined(_UEFI) && !defined(CRYPTOPP_DISABLE_ASM) && \
+	(defined(__SHA__) || defined(__INTEL_COMPILER) || CRYPTOPP_SHANI_AVAILABLE)
+#define TC_SHA256_PROBE_AVAILABLE
 extern int TrySHA256();
 #endif
 
@@ -366,7 +369,7 @@ void DetectX86Features()
 	}
 #endif
 
-#if defined(__SHA__) || defined(__INTEL_COMPILER) || CRYPTOPP_SHANI_AVAILABLE
+#ifdef TC_SHA256_PROBE_AVAILABLE
 	if (!g_hasSHA256)
 	{
 		g_hasSHA256 = TrySHA256();

src/Crypto/cpu.h

@@ -236,7 +236,8 @@ extern "C" {
 #endif
 
 #define CRYPTOPP_CPUID_AVAILABLE
-#if !defined(CRYPTOPP_DISABLE_AESNI) && !defined(WOLFCRYPT_BACKEND)
+/* aes_hw_cpu_* come from the assembler module, which NOASM builds leave out */
+#if !defined(CRYPTOPP_DISABLE_AESNI) && !defined(WOLFCRYPT_BACKEND) && !defined(CRYPTOPP_DISABLE_ASM)
 #define TC_AES_HW_CPU
 #endif