Need help building with yocto/bitbake

bitbake/yocto are a cross-build system for making OS images for embedded projects. I'm trying to build a yocto image that includes PyNaCl as a dependency. There are a lot of other packages in the process that build flawlessly, but when it comes time to cross-build sodium and stuff, PyNaCl's setup.py break down. I've got a small patch that was necessary to get PyNaCl to even attempt to build, but it's thus far insufficient to the complete task and leaves me with the following error:

File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 564, in load_entry_point return get_distribution(dist).load_entry_point(group, name) File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2662, in load_entry_point return ep.load() File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2316, in load return self.resolve() File "/usr/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2322, in resolve module = __import__(self.module_name, fromlist=['__name__'], level=0) File "/usr/lib/python3.5/site-packages/crossbar/controller/cli.py", line 62, in <module> from crossbar.controller.node import _read_release_pubkey, _read_node_pubkey File "/usr/lib/python3.5/site-packages/crossbar/controller/node.py", line 44, in <module> from nacl.signing import SigningKey File "/usr/lib/python3.5/site-packages/nacl/signing.py", line 19, in <module> import nacl.bindings File "/usr/lib/python3.5/site-packages/nacl/bindings/__init__.py", line 17, in <module> from nacl.bindings.crypto_box import ( File "/usr/lib/python3.5/site-packages/nacl/bindings/crypto_box.py", line 18, in <module> from nacl._sodium import ffi, lib ImportError: No module named 'nacl._sodium'

This is the patch that allows PyNaCl to at least attempt to (And seemingly successfully) build libsodium:

From 63a491f190645eb649308fec3186f8fd07236376 Mon Sep 17 00:00:00 2001
From: Christ Schlacta <aarcane@aarcane.org>
Date: Tue, 17 Apr 2018 18:08:11 -0700
Subject: [PATCH] modify setup.py to actually work


 setup.py | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)
 mode change 100644 => 100755 setup.py

diff --git a/setup.py b/setup.py
old mode 100644
new mode 100755
index eaa3e23..34ba3ed
--- a/setup.py
+++ b/setup.py
@@ -39,10 +39,12 @@ except ImportError:
 
 requirements = ["six"]
 setup_requirements = []
-test_requirements = ["pytest>=3.2.1,!=3.3.0",
-                     "hypothesis>=3.27.0"]
-docs_requirements = ["sphinx>=1.6.5",
-                     "sphinx_rtd_theme"]
+test_requirements = []
+docs_requirements = []
+#test_requirements = ["pytest>=3.2.1,!=3.3.0",
+#                     "hypothesis>=3.27.0"]
+#docs_requirements = ["sphinx>=1.6.5",
+#                     "sphinx_rtd_theme"]
 
 
 if platform.python_implementation() == "PyPy":
@@ -52,8 +54,9 @@ if platform.python_implementation() == "PyPy":
             "upgrade PyPy to use this library."
         )
 else:
-    requirements.append("cffi>=1.4.1")
-    setup_requirements.append("cffi>=1.4.1")
+    #requirements.append("cffi>=1.4.1")
+    #setup_requirements.append("cffi>=1.4.1")
+	pass
 
 
 def here(*paths):
@@ -167,6 +170,7 @@ class build_clib(_build_clib):
                 configure, "--disable-shared", "--enable-static",
                 "--disable-debug", "--disable-dependency-tracking",
                 "--with-pic", "--prefix", os.path.abspath(self.build_clib),
+				"--host", "arm-poky-linux-gnueabi"
             ],
             cwd=build_temp,
         )
@@ -176,7 +180,7 @@ class build_clib(_build_clib):
         subprocess.check_call(["make"] + make_args, cwd=build_temp)
 
         # Check the build library
-        subprocess.check_call(["make", "check"] + make_args, cwd=build_temp)
+        # subprocess.check_call(["make", "check"] + make_args, cwd=build_temp)
 
         # Install the built library
         subprocess.check_call(["make", "install"] + make_args, cwd=build_temp)
-- 
2.7.4

and lastly the recipe for PyNaCl in bitbake/yocto: python3-pynacl_1.2.1.bb

inherit setuptools3
DESCRIPTION = "PyNaCl is a Python binding to libsodium, which is a fork of the Networking and Cryptography library."
HOMEPAGE = "https://pypi.org/project/PyNaCl/"
LICENSE = "Apache-2.0"
LIC_FILES_CHKSUM = "file://LICENSE;md5=8cc789b082b3d97e1ccc5261f8594d3f"

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"

SRC_URI += "file://0001-modify-setup.py-to-actually-work.patch"


DEPENDS += " \
	${PYTHON_PN}-cffi \
	${PYTHON_PN}-six \
	${PYTHON_PN}-pycparser \
	${PYTHON_PN}-hypothesis \
	${PYTHON_PN}-pytest \
	"

RDEPENDS_${PN} += " \
	${PYTHON_PN}-cffi \
	${PYTHON_PN}-six \
	${PYTHON_PN}-pycparser \
	${PYTHON_PN}-hypothesis \
	${PYTHON_PN}-pytest \
	"

RDEPENDS_${PN}_class-target += " \
	${PYTHON_PN}-cffi \
	${PYTHON_PN}-six \
	${PYTHON_PN}-pycparser \
	${PYTHON_PN}-hypothesis \
	${PYTHON_PN}-pytest \
	"

SRC_URI[md5sum] = "1db3e111775fbe6b66772ff30af7a956"
SRC_URI[sha256sum] = "e0d38fa0a75f65f556fb912f2c6790d1fa29b7dd27a1d9cc5591b281321eaaa9"

PYPI_PACKAGE = "PyNaCl"

export SODIUM_INSTALL="bundled"

inherit pypi

Start with setup.py and the python3-pynacl_1.2.1.bb recipe, then reproduce the Yocto/BitBake build using the reported cross-build configuration. Trace the nacl._sodium import failure and verify that the resulting image builds PyNaCl successfully and can import its sodium bindings.