Oh, I was referring to the features.h failure, while @knc1 was talking about the curses failure
. Oops ^^.
So, to recap:
* As you've found out, and as my previous message explained: DO NOT pass --sysroot to the compiler. You're more likely to get it wrong than anything, and it isn't needed with a ct-ng TC anyway.
* As @knc1 mentioned, you need to cross-build the full dependency tree, install it in a common staging location (which you can see as another "sysroot"), and update your *FLAGS to pass include/lib locations to the compiler & linker (i.e, something along the lines of -I/blah/blah/include in CPPFLAGS (or CFLAGS for broken buildsystems) and -L/blah/blah/lib in LDFLAGS). Or help build-systems do that themselves (that may include, in the generally easiest of cases, just pointing pkg-config to your staging sysroot; or, in the worst cases, dealing with inane hoop-jumping for "next-generation" buildsystems like CMake & Meson).
Do follow @knc1's suggestion and try to find sane information about all this, because it is generally NOT trivial (it ought to, and seems to in theory, but is often not in practice).
You can see my various rants about all of this all over the place in the x-compile.sh script...