pcsc: Allow to disable the PCSC dependency

* PCSC is enabled by default
* --enable-pcsc is enabling it
* --disable-pcscis disabling it
* Fix the makefile of the utilities to not build pcsc and
use the right header files/libraries.
select.c: Add missing #include lines for string.h and sys/select.h

This is needed on Nuttx.
strrb.c: Use string.h, not strings.h

Not all systems have strings.h
remove references to u_char type, use 'unsigned char' instead

... u_char not being defined on Nuttx.
remove references to u_long type, use 'unsigned long' instead

.. Nuttx doesn't know u_long
vty/vector.c: Use string.h, not memory.h