Fix sdist and packaging

wolfcrypt was not being packaged in the sdist and the build system did
not work if the source wasn't a git checkout. Both fixed.

setup.py

@@ -26,11 +26,6 @@ import sys
 from setuptools import setup
 from setuptools.command.build_ext import build_ext
 
-
-# Adding src folder to the include path in order to import from wolfcrypt
-package_dir = os.path.dirname(__file__)
-sys.path.insert(0, package_dir)
-
 import wolfcrypt
 from wolfcrypt._build_wolfssl import build_wolfssl
 
@@ -69,7 +64,6 @@ setup(
     license=wolfcrypt.__license__,
 
     packages=["wolfcrypt"],
-    package_dir={"":package_dir},
 
     zip_safe=False,
     cffi_modules=["./wolfcrypt/_build_ffi.py:ffibuilder"],

wolfcrypt/_build_wolfssl.py

@@ -33,7 +33,6 @@ def local_path(path):
     current = os.path.abspath(os.getcwd())
     return os.path.abspath(os.path.join(current, path))
 
-
 WOLFSSL_SRC_PATH = local_path("lib/wolfssl")
 
 
@@ -121,8 +120,10 @@ def checkout_version(version):
 def ensure_wolfssl_src(ref):
     """ Ensure that wolfssl sources are presents and up-to-date
     """
-    if not os.path.isdir(WOLFSSL_SRC_PATH):
-        os.mkdir(WOLFSSL_SRC_PATH)
+    if not os.path.isdir("lib"):
+        os.mkdir("lib")
+        with chdir("lib"):
+            subprocess.run(["git", "clone", "--depth=1", "https://github.com/wolfssl/wolfssl"])
 
     if not os.path.isdir(os.path.join(WOLFSSL_SRC_PATH, "wolfssl")):
         subprocess.run(["git", "submodule", "update", "--init", "--depth=1"])