How can I solve "Unable to load native library ... dlopen failed: cannot locate symbol "ffi_type_void" referenced by ..."

[mutantbob]

I am working on an android VR app that works with cargo apk run.
I have completed an earlier app that can draw objects (suzanne and a color triangle) in VR.
I am moving to the next step where I want to use gstreamer to provide video for a texture, but if I call gst::init() in my code, I get this error at run time:

2023-06-28 10:47:25.869 24722-24722/rust.openxr_gst D/AndroidRuntime: Shutting down VM
2023-06-28 10:47:25.873 24722-24722/rust.openxr_gst E/AndroidRuntime: FATAL EXCEPTION: main
    Process: rust.openxr_gst, PID: 24722
    java.lang.UnsatisfiedLinkError: Unable to load native library "/data/app/~~FA8MGKpl2mLhXMiDdEkMWw==/rust.openxr_gst-KtRUUHinSBxQJoTnbLGurA==/lib/arm64/libopenxr_gst.so": dlopen failed: cannot locate symbol "ffi_type_void" referenced by "/data/app/~~FA8MGKpl2mLhXMiDdEkMWw==/rust.openxr_gst-KtRUUHinSBxQJoTnbLGurA==/lib/arm64/libopenxr_gst.so"...
        at android.app.NativeActivity.onCreate(NativeActivity.java:178)
        at android.app.Activity.performCreate(Activity.java:8057)
        at android.app.Activity.performCreate(Activity.java:8037)

calling gst::init() causes my app to refer to several undefined symbols in the .so

$ nm ./target/aarch64-linux-android/debug/*.so | grep ffi_type
                 U ffi_type_double
                 U ffi_type_float
                 U ffi_type_pointer
                 U ffi_type_sint32
                 U ffi_type_sint64
                 U ffi_type_uint32
                 U ffi_type_uint64
                 U ffi_type_void
000000000038535c t value_from_ffi_type
000000000038515c t value_to_ffi_type

How can I figure out which crate is depending on these, and then figure out how to link in the proper library to satisfy those symbols?

[H2CO3]

Those symbols are from libffi, a widely-used JITed C interop library. It looks like your library is dynamically linked to libffi. You may want to find the appropriate libffi.so and copy it over next to your library. (If this is a cross-compile, you should install it on your target system instead.)

[mutantbob]

One of my coworkers was able to find another project that uses libffi and suggested I add -lffi to my RUSTFLAGS, which got me to the next explosion (which is unrelated).