libffi: set FFI_MMAP_EXEC_WRIT and unset FFI_MMAP_EXEC_SELINUX on Android
libffi: set FFI_MMAP_EXEC_WRIT and unset FFI_MMAP_EXEC_SELINUX on Android

This fixes a crash on Android
Found here: https://github.com/frida/frida/blob/d3679e46df36986beca03da59be7acd691b6babe/releng/config.site.in#L119 (thanks to @oleavr)

shoreflyer/cerbero,ramaxlo/cerbero,sdroege/cerbero,ikonst/cerbero,EricssonResearch/cerbero,multipath-rtp/cerbero,ikonst/cerbero,ramaxlo/cerbero,sdroege/cerbero,AlertMe/cerbero,ramaxlo/cerbero,AlertMe/cerbero,shoreflyer/cerbero,multipath-rtp/cerbero,shoreflyer/cerbero,AlertMe/cerbero,sdroege/cerbero,AlertMe/cerbero,sdroege/cerbero,multipath-rtp/cerbero,EricssonResearch/cerbero,ramaxlo/cerbero,EricssonResearch/cerbero,sdroege/cerbero,multipath-rtp/cerbero,multipath-rtp/cerbero,ikonst/cerbero,EricssonResearch/cerbero,ikonst/cerbero,shoreflyer/cerbero,EricssonResearch/cerbero,shoreflyer/cerbero,ikonst/cerbero,ramaxlo/cerbero,AlertMe/cerbero