Removed MSVC check.

setup.py

@@ -1,35 +1,7 @@
 #!/usr/bin/python3
 
-import platform
+from setuptools import setup, Extension
 
-from setuptools import setup, find_packages, Extension
-from distutils.ccompiler import new_compiler
-from distutils.msvccompiler import MSVCCompiler
-
-
-def is_msvc():
-    '''Checks to see if the detected C compiler is MSVC.'''
-    try:
-        # This depends on _winreg, which is not available on not-Windows.
-        from distutils.msvc9compiler import MSVCCompiler as MSVC9Compiler
-    except ImportError:
-        MSVC9Compiler = None
-    try:
-        from distutils._msvccompiler import MSVCCompiler as MSVC14Compiler
-    except ImportError:
-        MSVC14Compiler = None
-    msvc_classes = tuple(filter(None, (MSVCCompiler,
-                                       MSVC9Compiler,
-                                       MSVC14Compiler)))
-    cc = new_compiler()
-    return isinstance(cc, msvc_classes)
-
-
-macros = []
-
-# MSVC won't use <math.h> unless this is defined.
-if platform.system() == 'Windows' and is_msvc():
-    macros.append(('_USE_MATH_DEFINES', None))
 
 extensions = [
     Extension(
@@ -43,7 +15,15 @@ extensions = [
             'src/lib/ebur128',
             'src/lib/ebur128/queue',
         ],
-        define_macros=macros,
+        # Not happy about it, but I'll just use this macro on all compilers for
+        # now. Setuptools doesn't have a reliable way to detect MSVC when they
+        # started deprecating the older distutils functionality of MSVCCompiler
+        # and new_compiler(). Besides, looking at the old distutils code, it
+        # just assumed that MSVC was the compiler if it detected Windows. If you
+        # wanted GCC/MinGW/LLVM on Windows, you had to manually pass it as an
+        # argument to new_compiler().
+        # See https://github.com/pypa/setuptools/issues/2806
+        define_macros=[('_USE_MATH_DEFINES', None)],
     ),
 ]