diff --git a/configure.ac b/configure.ac
index 44608bff26..863943a23d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -465,7 +465,7 @@ ERROR: could not find (recent enough) development-libs for libcurl.
 fi
 
 dnl ---------- SSL (m4/check_ssl.m4)
-if test "x${enable_client}" = xyes -o test "x${enable_server}" = xyes]; then
+if ( test "x${enable_client}" = xyes ) -o ( test "x${enable_server}" = xyes ); then
     CHECK_SSL
     if test "x${found_ssl}" = "xyes"; then
        BOINC_EXTRA_LIBS="${BOINC_EXTRA_LIBS} ${SSL_LIBS}"