split mesonlib into a package

Currently mesonlib does some import tricks to figure out whether it
needs to use windows or posix specific functions. This is a little
hacky, but works fine. However, the way the typing stubs are implemented
for the msvcrt and fnctl modules will cause mypy to fail on the other
platform, since the functions are not implemented.

To aleviate this (and for slightly cleaner design), I've split mesonlib
into a pacakge with three modules. A universal module contains all of
the platform agnositc code, a win32 module contains window specific
code, a posix module contains the posix specific code, and a platform
module contains no-op implementations. Then the package's __init__ file
imports all of the universal functions and all of the functions from the
approriate platform module, or the no-op versions as fallbacks. This
makes mypy happy, and avoids `if`ing all over the code to switch between
the platform specific code.

1 files changed, 2 insertions, 1 deletions

diff --git a/mesonbuild/compilers/c.py b/mesonbuild/compilers/c.py
index c11319b..0a2d478 100644
--- a/mesonbuild/compilers/c.py
+++ b/mesonbuild/compilers/c.py
@@ -16,7 +16,8 @@ import os.path
 import typing as T
 
 from .. import coredata
-from ..mesonlib import MachineChoice, MesonException, mlog, version_compare, OptionKey
+from .. import mlog
+from ..mesonlib import MachineChoice, MesonException, version_compare, OptionKey
 from .c_function_attributes import C_FUNC_ATTRIBUTES
 from .mixins.clike import CLikeCompiler
 from .mixins.ccrx import CcrxCompiler