m4/dnstap.m4: new

m4/dnstap.m4

+# dnstap.m4
+
+# dt_DNSTAP([action-if-true], [action-if-false])
+# --------------------------------------------------------------------------
+# Check for required dnstap libraries and add dnstap configure args.
+AC_DEFUN([dt_DNSTAP],
+[
+  AC_ARG_ENABLE([dnstap],
+    AS_HELP_STRING([--enable-dnstap],
+                   [Enable dnstap support (requires fstrm, protobuf-c)]),
+    [opt_dnstap=$enableval], [opt_dnstap=no])
+
+  if test "x$opt_dnstap" != "xno"; then
+    AC_PATH_PROG([PROTOC_C], [protoc-c])
+    if test -z "$PROTOC_C"; then
+      AC_MSG_ERROR([The protoc-c program was not found. Please install protobuf-c!])
+    fi
+    PKG_CHECK_MODULES([libfstrm], [libfstrm])
+    PKG_CHECK_MODULES([libprotobuf_c], [libprotobuf-c >= 1.0.0])
+    DNSTAP_CFLAGS="$libfstrm_CFLAGS $libprotobuf_c_CFLAGS"
+    DNSTAP_LIBS="$libfstrm_LIBS $libprotobuf_c_LIBS"
+    $1
+  m4_ifvaln([$2], [else
+    $2])dnl
+  fi
+])