component/m4: use buildout patch instead of system patch

component/m4/buildout.cfg

 [buildout]
 extends =
   ../xz-utils/buildout.cfg
+  ../patch/buildout.cfg
 parts =
   m4
 
@@ -10,7 +11,7 @@ shared = true
 url = http://ftp.gnu.org/gnu/m4/m4-1.4.18.tar.xz
 md5sum = 730bb15d96fffe47e148d1e09235af82
 environment =
-  PATH=${xz-utils:location}/bin:%(PATH)s
+  PATH=${xz-utils:location}/bin:${patch:location}/bin:%(PATH)s
 patch-options = -p1
 patches =
   ${:_profile_base_location_}/01-fix-ftbfs-with-glibc-2.28.patch#058a786425e507f911649205b61ffcac