diff --git a/firefox-mozconfig-debuginfo b/firefox-mozconfig-debuginfo
index a0ef07a..8a874b4 100644
--- a/firefox-mozconfig-debuginfo
+++ b/firefox-mozconfig-debuginfo
@@ -1,5 +1,5 @@
 # For mozilla's debuginfo:
-export CFLAGS="-gstabs+"
-export CXXFLAGS="-gstabs+"
+export CFLAGS="$CFLAGS -gstabs+"
+export CXXFLAGS="$CXXFLAGS -gstabs+"
 export MOZ_DEBUG_SYMBOLS=1
 ac_add_options --enable-crashreporter