diff --git a/Makefile.prebuild b/Makefile.prebuild
index 399db956f..4dad74d63 100644
--- a/Makefile.prebuild
+++ b/Makefile.prebuild
@@ -71,7 +71,8 @@ endif
 
 
 getarch : getarch.c cpuid.S dummy $(CPUIDEMU)
-	$(HOSTCC) $(HOST_CFLAGS) $(EXFLAGS) -o $(@F) getarch.c cpuid.S $(CPUIDEMU)
+	avx512=$$(perl c_check - - gcc | grep NO_AVX512); \
+	$(HOSTCC) $(HOST_CFLAGS) $(EXFLAGS) $${avx512:+-D$${avx512}} -o $(@F) getarch.c cpuid.S $(CPUIDEMU)
 
 getarch_2nd : getarch_2nd.c config.h dummy
 ifndef TARGET_CORE
diff --git a/c_check b/c_check
index 999f5a7a7..e10ddfebc 100644
--- a/c_check
+++ b/c_check
@@ -254,7 +254,7 @@ if (($architecture eq "x86") || ($architecture eq "x86_64")) {
 #	$tmpf = new File::Temp( UNLINK => 1 );
 	($fh,$tmpf) = tempfile( SUFFIX => '.c' , UNLINK => 1 );
 	$code = '"vbroadcastss -4 * 4(%rsi), %zmm2"';
-	print $tmpf "#include <immintrin.h>\n\nint main(void){ __asm__ volatile($code); }\n";
+	print $fh "#include <immintrin.h>\n\nint main(void){ __asm__ volatile($code); }\n";
 	$args = " -march=skylake-avx512 -c -o $tmpf.o $tmpf";
 	if ($compiler eq "PGI") {
 	    $args = " -tp skylake -c -o $tmpf.o $tmpf";
@@ -278,7 +278,7 @@ if ($data =~ /HAVE_C11/) {
        $c11_atomics = 0;
     } else {
        ($fh,$tmpf) = tempfile( SUFFIX => '.c' , UNLINK => 1 );
-       print $tmpf "#include <stdatomic.h>\nint main(void){}\n";
+       print $fh "#include <stdatomic.h>\nint main(void){}\n";
        $args = " -c -o $tmpf.o $tmpf";
        my @cmd = ("$compiler_name $flags $args >/dev/null 2>/dev/null");
        system(@cmd) == 0;
diff --git a/getarch.c b/getarch.c
index 00e544bc7..e49eac1a3 100644
--- a/getarch.c
+++ b/getarch.c
@@ -94,14 +94,6 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <sys/sysinfo.h>
 #endif
 
-#if defined(__x86_64__) || defined(_M_X64)
-#if (( defined(__GNUC__)  && __GNUC__   > 6 && defined(__AVX2__)) || (defined(__clang__) && __clang_major__ >= 6))
-#else
-#ifndef NO_AVX512
-#define NO_AVX512
-#endif
-#endif
-#endif
 /* #define FORCE_P2		*/
 /* #define FORCE_KATMAI		*/
 /* #define FORCE_COPPERMINE	*/