Remove option incompatible with Debian hardening.

Forwarded: not-needed
diff --git a/build/gen.py b/build/gen.py
index d1c649cb..96a83f75 100755
--- a/build/gen.py
+++ b/build/gen.py
@@ -515,7 +515,6 @@ def WriteGNNinja(path, platform, host, options, args_list):
         '-Wno-implicit-fallthrough',
         '-Wno-redundant-move',
         '-Wno-unused-variable',
-        '-Wno-format',             # Use of %llx, which is supported by _UCRT, false positive
         '-Wno-strict-aliasing',    # Dereferencing punned pointer
         '-Wno-cast-function-type', # Casting FARPROC to RegDeleteKeyExPtr
       ])