Feature: Add support for building under Android.

Feature: Add support for building under Android.

This is a forward port of the changes from the 0.6 branch without any testing.

This is not well tested or well supported.
This does have limited testing under the Termux project environment using CLang.

Add a new configuration option to build and run the project in an Android environment.

The test system had problems with text relocations but then required PIE.
This disables the relro in some spots (libraries) while enabling it in others (programs/executables).

Disable a lot of the functions that are not available or supported.

I have observed several warnings about `DT_FLAGS_1=0x41` being unsupported flag.
That is not a very helpful warning.
I have no idea what `0x41` is.
This causes a problem where the output of programs displays these warnings.
This can break programs that require I/O formatting and processing.

This has been tested to build using `bootstrap.sh` and then using `fake`.
Example build and install process:
# mkdir ~/software
# cd fll-0.6.X/
# ./bootstrap.sh build -m monolithic -m thread -m clang -m android && ./install.sh ~/software
# cd ../fake-0.6.X/
# ./bootstrap.sh build -m monolithic -m thread -m clang -m android -w ~/software && ./install.sh ~/software
# export LD_LIBRARY_PATH=~/software/libraries/shared
# export PATH=~/software/programs/shared
# cd ../byte_dump-0.6.X/
# fake -m monolithic -m thread -m clang -m android -w ~/software && ./install.sh ~/software

Example execution of `byte_dump` of `bash` program (this is a large dump).
# byte_dump -wt 7 $(type -p bash)