Signed-off-by: Pablo Galindo <pablogsal@gmail.com>

These environment variables previously allowed us to conditionally
enable extra safety checks in our Cython code, or conditionally disable
optimizations that might break tools like Valgrind. Now, we control this
based on the CMake build type, so that release builds have the extra
optimizations and debug builds don't, and so that debug builds have the
extra safety checks and release builds don't.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

Some tests were erroneously removing all environment variables from the
environment and passing along an environment consisting of only a single
variable. Since this removes environment variables like $PATH, this
breaks automatic rebuilds -- they can't find the compiler!

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

This test failed in CI because the same time was captured in both
`end_time` and `start_time`. There's no reason to assume that this took
more than a millisecond, or that the system clock can give us better
than millisecond granularity, so it seems more reasonable to simply
check that the end time is no earlier than the start time. Technically
even that assumption could be violated, since we're not using
a monotonic clock, but oh well, this is just tests.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

We meant to ignore any Makefile generated by CMake, but we shouldn't be
ignoring our own hand-written Makefile.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

`setuptools` uses CFLAGS for both C and C++ builds, but CMake
distinguishes between them, and only uses CXXFLAGS for C++ builds.
Whenever we want to set flags that affect both C and C++ builds, ensure
that we set both CFLAGS and CXXFLAGS.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

With `scikit-build-core`, we don't have any way to produce an entry
point script called `memray3.N` (where `3.N` is the Python version
Memray was installed for). Drop references to it from the docs.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

With an editable `scikit-build-core` install, shared libraries are not
in the same directory as Python files, so we can no longer locate it
relative to `__init__.py`.

Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>