Check compiler for relro support instead of linker

We use the compiler for linking in most cases
instead of calling ld directly.

Do this the same way as we do for the recursor.
Fixes #2172

(cherry picked from commit cc8ac2e97d16c01a6e4c10914d848d228f7494b5)

diff --git a/m4/pdns_relro.m4 b/m4/pdns_relro.m4
index 3493d72a1274695cb390d5f6ac5525e44a3e0f46..4f93629a8e98f8ffbc5394cdb629504794b81d52 100644 (file)
--- a/m4/pdns_relro.m4
+++ b/m4/pdns_relro.m4
@@ -22,7 +22,7 @@ AC_DEFUN([AC_LD_RELRO],[
     AC_MSG_CHECKING([for how to force completely read-only GOT table])
 
     RELRO_LDFLAGS=
-    ld_help=`$LD --help 2>&1`
+    ld_help=`$CXX -Wl,-help 2>&1`
     case $ld_help in
         *"-z relro"*) RELRO_LDFLAGS="-Wl,-z -Wl,relro" ;;
     esac