Squashed commit of the following:
configs/makerlisp/scripts/makerlisp_ram.linkcmd: Fixup .RESET and .STARTUP. These need to be redirected to RAM since they default to ROM.
configs/makerlisp/scripts/makerlisp_ram.linkcmd: Restore some settings that should be unnecessary but are really required by the current implementation.
configs/makerlisp: Rename nsh configuratinon to nsh_flash. Create new configuration, nsh_ram, that is identical to the nsh_flash configuration except that the code runs out of external SRAM.
configs/makerlisp/scripts: Add a linker script to support execution from RAM.
Squashed commit of the following:
configs/makerlisp: Update comments about use of serial console.
configs/makerlisp: Add LED support, remove vestiges of button support (the board has no user buttons). Add support for SPI-based MMC/SD card slot.
arch/z80/src/ez80: Fix some link problems.
libs/libc/syslog/lib_syslog.c: The ZDS-II toolchain does not declare va_coy in stdarg.h. I think that the use of va_copy in vsyslog() is no necessary.
configs/makerlisp: Initial configuration directories cloned from ez80f910200zco with little more than naming changes.
