Can still be enabled by passing --cmake-warn-uninitialized on the command line
Prevents CMake warnings printed by default if IDF_PATH is underneath the CMake
project directory.
The reason for this is that CMake --warn-uninitialized only enables checks
inside the project directory (ie top-level CMakeLists.txt directory and
subdirectories), it doesn't enable for files included from other directories.
(The only way to enable warnings in other directories is to pass
--check-system-dirs and this looks like it's only useful for CMake's own
developers as it prints a lot of warnings from inside CMake otherwise - see
https://gitlab.kitware.com/cmake/cmake/-/issues/19645 )
Plan to follow up with a later commit to clean up most of the warnings (which
aren't problems for CMake execution), but we'll also disable this option by
default to avoid this unexpected triggering of IDF warnings.
1. Call cli with explicit argv
When using debugging tools like `pydbg.py --some_arg idf.py -G Ninga
build`, those tools usually call the python script with sys.argv
modified to correct value. But if the cli is called with argv blank, the
cli will get the argv again, and finally get the original command line,
which is incorrect for debugging.
2. Encode the style unicode string back to ascii in menuconfig cmd
On Windows MSYS python2.7, the unicode string set in os.environ will
cause the subprocess creating to fail. All os.environ values should be
strings.
