xbps-src: source msg_warn before its first use

xbps-src

@@ -689,12 +689,6 @@ fi
 
 check_build_requirements
 
-if [ -z "$IN_CHROOT" ]; then
-    trap 'exit_func' INT TERM
-    if [ -n "$XBPS_DISTFILES_MIRROR" ]; then
-        setup_distfiles_mirror
-    fi
-fi
 #
 # Read funcs from helpers
 #
@@ -702,6 +696,13 @@ for f in ${XBPS_SHUTILSDIR}/*.sh; do
     [ -r "$f" ] && . $f
 done
 
+if [ -z "$IN_CHROOT" ]; then
+    trap 'exit_func' INT TERM
+    if [ -n "$XBPS_DISTFILES_MIRROR" ]; then
+        setup_distfiles_mirror
+    fi
+fi
+
 reconfigure_base_chroot
 
 #