First try at implementing optionsfor allowing different manylinux1 docker images

test/06_docker_images/environment.json

@@ -0,0 +1,5 @@
+{
+    "CIBW_MANYLINUX1_X86_64_IMAGE": "dockcross/manylinux-x64",
+    "CIBW_MANYLINUX1_I686_IMAGE": "dockcross/manylinux-x86",
+    "CIBW_SKIP": "*macos* *win*"
+}

test/06_docker_images/setup.py

@@ -0,0 +1,12 @@
+import os
+
+from setuptools import setup, Extension
+
+if os.environ.get('CIBUILDWHEEL', '0') != '1':
+    raise Exception('CIBUILDWHEEL environment variable is not set to 1')
+
+setup(
+    name="spam",
+    ext_modules=[Extension('spam', sources=['spam.c'])],
+    version="0.1.0",
+)

test/06_docker_images/spam.c

@@ -0,0 +1,48 @@
+#include <Python.h>
+
+static PyObject *
+spam_system(PyObject *self, PyObject *args)
+{
+    const char *command;
+    int sts;
+
+    if (!PyArg_ParseTuple(args, "s", &command))
+        return NULL;
+    sts = system(command);
+    return PyLong_FromLong(sts);
+}
+
+/* Module initialization */
+
+#if PY_MAJOR_VERSION >= 3
+    #define MOD_INIT(name) PyMODINIT_FUNC PyInit_##name(void)
+    #define MOD_DEF(m, name, doc, methods, module_state_size) \
+        static struct PyModuleDef moduledef = { \
+            PyModuleDef_HEAD_INIT, name, doc, module_state_size, methods, }; \
+        m = PyModule_Create(&moduledef);
+    #define MOD_RETURN(m) return m;
+#else
+    #define MOD_INIT(name) PyMODINIT_FUNC init##name(void)
+    #define MOD_DEF(m, name, doc, methods, module_state_size) \
+        m = Py_InitModule3(name, methods, doc);
+    #define MOD_RETURN(m) return;
+#endif
+
+static PyMethodDef module_methods[] = {
+    {"system", (PyCFunction)spam_system, METH_VARARGS, 
+     "Execute a shell command."},
+    {NULL}  /* Sentinel */
+};
+
+MOD_INIT(spam)
+{
+    PyObject* m;
+
+    MOD_DEF(m, 
+            "spam", 
+            "Example module", 
+            module_methods,
+            -1)
+
+    MOD_RETURN(m)
+}