2 files changed, 25 insertions, 5 deletions

diff --git a/configure b/configure
index 0ccaad051..9a7d91111 100755
--- a/configure
+++ b/configure
@@ -3106,20 +3106,36 @@ fi
 
 
 HAVE_SPECTRE="no"
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Spectre mitigation support in gcc compiler" >&5
-$as_echo_n "checking for Spectre mitigation support in gcc compiler... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Spectre mitigation support in gcc or clang compiler" >&5
+$as_echo_n "checking for Spectre mitigation support in gcc or clang compiler... " >&6; }
 if test "$CC" = "gcc"; then :
 
         HAVE_SPECTRE="yes"
         $CC -mindirect-branch=thunk -c dummy.c || HAVE_SPECTRE="no"
         rm -f dummy.o
+        if test "$HAVE_SPECTRE" = "yes"; then :
+
+                EXTRA_CFLAGS+=" -mindirect-branch=thunk "
+
+fi
+
+fi
+if test "$CC" = "clang"; then :
+
+        HAVE_SPECTRE="yes"
+        $CC -mretpoline -c dummy.c || HAVE_SPECTRE="no"
+        rm -f dummy.o
+        if test "$HAVE_SPECTRE" = "yes"; then :
+
+                EXTRA_CFLAGS+=" -mretpoline "
+
+fi
 
 fi
 if test "$HAVE_SPECTRE" = "yes"; then :
 
         { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
-        EXTRA_CFLAGS+=" -mindirect-branch=thunk "
 
 fi
 if test "$HAVE_SPECTRE" = "no"; then :
diff --git a/configure.ac b/configure.ac
index 1f573d50f..d3405a135 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,13 +14,17 @@ AS_IF([test "$CC" = "gcc"], [
         HAVE_SPECTRE="yes"
         $CC -mindirect-branch=thunk -c dummy.c || HAVE_SPECTRE="no"
         rm -f dummy.o
-        EXTRA_CFLAGS+=" -mindirect-branch=thunk "
+        AS_IF([test "$HAVE_SPECTRE" = "yes"], [
+                EXTRA_CFLAGS+=" -mindirect-branch=thunk "
+        ])
 ])
 AS_IF([test "$CC" = "clang"], [
         HAVE_SPECTRE="yes"
         $CC -mretpoline -c dummy.c || HAVE_SPECTRE="no"
         rm -f dummy.o
-        EXTRA_CFLAGS+=" -mretpoline "
+        AS_IF([test "$HAVE_SPECTRE" = "yes"], [
+                EXTRA_CFLAGS+=" -mretpoline "
+        ])
 ])
 AS_IF([test "$HAVE_SPECTRE" = "yes"], [
         AC_MSG_RESULT(yes)