diff --git a/configure.ac b/configure.ac
index 663242ff2..1165d5061 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1116,18 +1116,6 @@ then
             fi
         fi
         AS_IF([test "x$ENABLED_AESGCM" != "xno"],[AM_CCASFLAGS="$AM_CCASFLAGS -DHAVE_AESGCM"])
-
-    elif test "$host_cpu" = "x86_64"
-    then
-        if test "$GCC" = "yes"
-        then
-            # GCC needs these flags, icc doesn't
-            # opt levels greater than 2 may cause problems on systems w/o aesni
-            if test "$CC" != "icc"
-            then
-                AM_CFLAGS="$AM_CFLAGS -msse4"
-            fi
-        fi
     fi
 
     if test "$ENABLED_INTELASM" = "yes"
@@ -3373,7 +3361,7 @@ then
         [KERNEL_ARCH=$DEFAULT_KERNEL_ARCH])
     AC_SUBST([KERNEL_ARCH])
 
-    if test -z "${KERNEL_ROOT}"; then
+    if test "${KERNEL_ROOT}" = ""; then
         AC_MSG_ERROR([Linux kernel source root not found -- supply with --with-linux-source=PATH.])
     fi