The primary goal is to allow a binary to be built which supports
 NEON, but can fall back to non-NEON routines, since some Android
 devices do not have NEON, even if they are otherwise ARMv7 (e.g.,
 Tegra).
The configure-generated flags HAVE_ARMV7, etc., are used to decide
 which versions of each function to build, and when
 CONFIG_RUNTIME_CPU_DETECT is enabled, the correct version is chosen
 at run time.
In order for this to work, the CFLAGS must be set to something
 appropriate (e.g., without -mfpu=neon for ARMv7, and with
 appropriate -march and -mcpu for even earlier configurations), or
 the native C code will not be able to run.
The ASFLAGS must remain set for the most advanced instruction set
 required at build time, since the ARM assembler will refuse to emit
 them otherwise.
I have not attempted to make any changes to configure to do this
 automatically.
Doing so will probably require the addition of new configure options.

Many of the hooks for RTCD on A...