- merge the PICO_BOARD and PIP_FREERTOS blocks (90% duplicate) into one
embedded block; Pico+PICO_FREERTOS now adds -DPIP_FREERTOS so
pithread.cpp takes the FreeRTOS path instead of POSIX pthreads;
restore set(ICU OFF)/set(LOCAL ON) for FreeRTOS/embedded targets
- auto-disable dependent flags when PIP_HAS_THREADS=OFF:
PIP_HAS_PROCESS, PIP_HAS_SERIAL (PIProcess derives from PIThread,
PISerial/PIIODevice use PIThread) and INTROSPECTION (walks threads)
- LIBS_MAIN: link dl only with PIP_HAS_DYNLIB, pthread/util/rt only with
PIP_HAS_THREADS (rt was never linked on APPLE), socket on QNX_HOST only
with PIP_HAS_SOCKET; WIN32 list untouched - arm-none-eabi has no
libdl/libpthread/librt so Pico firmware links again
- collapse repeated 'NOT DEFINED PICO_SDK_PATH' utils checks into
_PIP_HOST_TOOLS variable
- FindPIP.cmake: check PIP_FREERTOS instead of the never-set
PIP_EMBEDDED CMake variable (as in master)
- drop unused set(PIP_MICRO ON) from esp-pip
- wrap PIGrabberBase/PIPipelineThread in #ifdef PIP_HAS_THREADS like
pithread.h so 'pip.h' compiles in no-threads builds