Why is glibmm said to require builddir == sourcedir builds?

[Kjell Ahlstedt <kjellahlstedt gmail com>]

From jhbuild/modulesets/gnome-suites-core-deps-latest.modules:

  <autotools id="glibmm-2.4" supports-non-srcdir-builds="no">
  <autotools id="glibmm" supports-non-srcdir-builds="no">

I've used jhbuild to build glibmm without the 
supports-non-srcdir-builds="no" parameter. I can't see nay problem. 
Everything seems to work normally in a builddir != sourcedir build: 
make, make install, make check, make distcheck.

Emmanuele, you added supports-non-srcdir-builds="no" to 
gnome-suites-core-deps-3.22.modules with commit
https://gitlab.gnome.org/GNOME/jhbuild/commit/c283a4b6af5d94cea7c90e5587fffad8e7ef0413
Do you remember why you did that?

I'm tempted to remove supports-non-srcdir-builds="no" from the glibmm 
and glibmm-2.4 entries in gnome-suites-core-deps-latest.modules.

Kjell