New configure option --enable-x86-sha-ni.

ChangeLog

+2018-02-10  Niels Möller  <nisse@lysator.liu.se>
+
+	* configure.ac: New configure option --enable-x86-sha-ni.
+
 2018-02-07  Niels Möller  <nisse@lysator.liu.se>
 
 	* x86_64/fat/sha1-compress.asm: New file.

configure.ac

@@ -85,6 +85,10 @@ AC_ARG_ENABLE(x86-aesni,
   AC_HELP_STRING([--enable-x86-aesni], [Enable x86_64 aes instructions. (default=no)]),,
   [enable_x86_aesni=no])
 
+AC_ARG_ENABLE(x86-sha-ni,
+  AC_HELP_STRING([--enable-x86-sha-ni], [Enable x86_64 sha_ni instructions. (default=no)]),,
+  [enable_x86_sha_ni=no])
+
 AC_ARG_ENABLE(mini-gmp,
   AC_HELP_STRING([--enable-mini-gmp], [Enable mini-gmp, used instead of libgmp.]),,
   [enable_mini_gmp=no])
@@ -405,9 +409,14 @@ if test "x$enable_assembler" = xyes ; then
 	if test "x$enable_fat" = xyes ; then
 	  asm_path="x86_64/fat $asm_path"
 	  OPT_NETTLE_SOURCES="fat-x86_64.c $OPT_NETTLE_SOURCES"
-	elif test "x$enable_x86_aesni" = xyes ; then
+	else
+	  if test "x$enable_x86_aesni" = xyes ; then
 	    asm_path="x86_64/aesni $asm_path"
 	  fi
+	  if test "x$enable_x86_sha_ni" = xyes ; then
+	    asm_path="x86_64/sha_ni $asm_path"
+	  fi
+	fi
       else
 	asm_path=x86
       fi