#433 Fails to build with C++11 or later

[Jonathan Wakely]

libs/core/texturing_old/shadowmap_old.cpp says if ( file != NULL ) which is only valid in C++98 (and was always poor style anyway). The implicit conversion to void* exists so that you can write if (file) directly. Comparing to NULL relies on a leaky abstraction.

C++11 replaced the implicit conversion to void* with an explicit conversion to bool, so the idiomatic if (file) still works, but your code doesn't.

I've attached a patch to fix it, which I'm including in Fedora's RPM build of aqsis.

[Jonathan Wakely]

See also https://bugzilla.redhat.com/show_bug.cgi?id=1307323