diff --git a/Makefile.in b/Makefile.in
index c8168bbe..eb6cc5c9 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -21,11 +21,6 @@ INSTALL=@INSTALL@
 INSTALL_PROGRAM=@INSTALL_PROGRAM@
 INSTALL_DATA=@INSTALL_DATA@
 
-git-label:=$(strip $(shell git describe --always --dirty=-x 2>/dev/null))
-ifneq ($(git-label),)
-        CFLAGS += -DGIT_LABEL="$(git-label)"
-endif
-
 client=$(addprefix $(exedir)/,@CLIENT@)
 daemon=$(exedir)/bird
 protocols=@protocols@
@@ -42,6 +37,11 @@ srcdir := @srcdir@
 objdir := @objdir@
 exedir := @exedir@
 
+git-label:=$(strip $(shell cd $(srcdir) && [ "$$(git rev-parse --show-toplevel)" = "$$(readlink -f .)" ] && git describe --always --dirty=-x 2>/dev/null))
+ifneq ($(git-label),)
+        CFLAGS += -DGIT_LABEL="$(git-label)"
+endif
+
 ifeq ($(objdir),.)
   objdir := $(realpath .)
 endif