sha/asm/sha{1|256}-586.pl: harmonize clang version detection.

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6499)

crypto/sha/asm/sha1-586.pl

@@ -144,7 +144,7 @@ $ymm=1 if ($xmm && !$ymm && $ARGV[0] eq "win32" &&
 		`ml 2>&1` =~ /Version ([0-9]+)\./ &&
 		$1>=10);	# first version supporting AVX
 
-$ymm=1 if ($xmm && !$ymm && `$ENV{CC} -v 2>&1` =~ /(^clang version|based on LLVM) ([3-9]\.[0-9]+)/ &&
+$ymm=1 if ($xmm && !$ymm && `$ENV{CC} -v 2>&1` =~ /((?:^clang|LLVM) version|based on LLVM) ([3-9]\.[0-9]+)/ &&
 		$2>=3.0);	# first version supporting AVX
 
 $shaext=$xmm;	### set to zero if compiling for 1.0.1

crypto/sha/asm/sha256-586.pl

@@ -96,7 +96,7 @@ if ($xmm && !$avx && $ARGV[0] eq "win32" &&
 	$avx = ($1>=10) + ($1>=11);
 }
 
-if ($xmm && !$avx && `$ENV{CC} -v 2>&1` =~ /(^clang version|based on LLVM) ([3-9]\.[0-9]+)/) {
+if ($xmm && !$avx && `$ENV{CC} -v 2>&1` =~ /((?:^clang|LLVM) version|based on LLVM) ([3-9]\.[0-9]+)/) {
 	$avx = ($2>=3.0) + ($2>3.0);
 }