Make LTO Patch for Job Server Thread Detection Agnostic

[Nicholas Krause]

Greetings Martin,

This patch:
https://gcc.gnu.org/git/?p=gcc.git;a=blobdiff;f=gcc/lto-wrapper.c;h=353187c60434f43a445e708dcfbf53c857f8cdc1;hp=946897726d03716f7c93f955c438ee4f8190044c;hb=f12fbeb535f192f742025cc4f9b69a48136730f1;hpb=80c7cb9d2c8090f8d165ee2ca5f8d401090c1d06

May have a small problem with the lines:
+  const char *makeflags = getenv ("MAKEFLAGS");
+  if (makeflags == NULL)
+    return false; I'm not sure if ninja or other build systems use that 
for detection or have it as a variable you can use. This may be an issue 
with ninja, cmake and other build systems that may not have it. Maybe 
I'm wrong but it may be good to check that, Nick