Merge branch 'maint-0.2.7' into maint-0.2.8

diff --cc configure.ac
index e4816fdbd75ed607d96682bd32797cadc1d04864,8107c905a5d14404b6fd2e9c214f059005c811d3..a4879487455de2c75b0a3d1cc6a36b986004a64c
--- 1/configure.ac
--- 2/configure.ac
+++ b/configure.ac
@@@ -760,9 -717,9 +760,9 @@@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], 
  #error
  #endif])], have_clang=yes, have_clang=no)
  
 -if test x$enable_gcc_hardening != xno; then
 +if test "x$enable_gcc_hardening" != "xno"; then
-     CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
+     CFLAGS="$CFLAGS -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2"
 -    if test x$have_clang = xyes; then
 +    if test "x$have_clang" = "xyes"; then
          TOR_CHECK_CFLAGS(-Qunused-arguments)
      fi
      TOR_CHECK_CFLAGS(-fstack-protector-all, also_link)