Fix build on macOS 12

Building on macOS 12 fails with the following error

> implicit declaration of function 'unzip' is invalid in C99

Since unzip is only used in lp.c, this commit moves the function from
util.c to lp.c, makes the function static, and adds an explicit function
declaration.

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-22.04, ubuntu-20.04]
+        os: [macos-12, ubuntu-22.04, ubuntu-20.04]
         glpk: ['4.65', '5.0']
         python-version: ['3.8', '3.9', '3.10', '3.11']
 
@@ -29,15 +29,28 @@ jobs:
         ./configure
         make -j $(nproc)
         sudo make install
-        sudo ldconfig
+        [[ $(uname) == Darwin ]] || sudo ldconfig
         popd
-    - name: install dependencies
+    - name: install lcov
       run: |
-        pip install setuptools_scm tox
-        sudo apt-get update -q=1 -y
-        sudo apt-get install -q=1 -y lcov
+        platform="$(uname)"
+        case "${platform}" in
+        Darwin)
+            brew update -q
+            HOMEBREW_NO_INSTALL_CLEANUP=true brew install -q lcov
+            ;;
+        Linux)
+            sudo apt-get update -q=1 -y
+            sudo apt-get install -q=1 -y lcov
+            ;;
+        *)
+            echo >&2 "Unknown platform '${platform}'; supported platforms are 'Darwin' and 'Linux'"
+            exit 1
+            ;;
+        esac
     - name: run tox
       run: |
+        pip install setuptools_scm tox
         tox -e py
         mkdir coverage
         lcov --capture --directory . --output-file ./coverage/lcov.info

src/lp.c

@@ -36,6 +36,7 @@ along with PyGLPK. If not, see <http://www.gnu.org/licenses/>.
 #define LP (self->lp)
 
 static PyObject* glpstatus2string(int);
+static int unzip(PyObject *, const int, BarObject *[], double []);
 
 static int LPX_traverse(LPXObject *self, visitproc visit, void *arg)
 {
@@ -1215,6 +1216,45 @@ static PyObject* LPX_getnumbin(LPXObject *self, void *closure)
 	return PyInt_FromLong(glp_get_num_bin(LP));
 }
 
+static int unzip(PyObject *iterator, const int len, BarObject *bars[], double val[]) {
+	if (!PyIter_Check(iterator)) {
+		PyErr_SetString(PyExc_TypeError, "object not iterable");
+		return -1;
+	}
+
+	PyObject *item;
+	int index = 0;
+	while ((item = PyIter_Next(iterator)) && (index < len)) {
+		if (!PyTuple_Check(item) || PyTuple_Size(item) != 2) {
+			PyErr_SetString(PyExc_TypeError, "item must be two element tuple");
+			Py_DECREF(item);
+			return -1;
+		}
+
+		PyObject *bo, *vo;
+		if ((bo = PyTuple_GetItem(item, 0)) == NULL || (vo = PyTuple_GetItem(item, 1)) == NULL) {
+			PyErr_SetString(PyExc_RuntimeError, "unable to unpack tuple");
+			Py_DECREF(item);
+			return -1;
+		}
+
+		if (!PyObject_TypeCheck(bo, &BarType) || !PyFloat_Check(vo)) {
+			PyErr_SetString(PyExc_TypeError, "tuple must contain glpk.Bar and double");
+			Py_DECREF(item);
+			return -1;
+		}
+
+		index += 1;
+
+		bars[index] = (BarObject *) bo;
+		val[index] = PyFloat_AsDouble(vo);
+
+		Py_DECREF(item);
+	}
+
+	return index;
+}
+
 /****************** OBJECT DEFINITION *********/
 
 int LPX_InitType(PyObject *module)

src/util.c

@@ -289,41 +289,3 @@ int PyDict_SetIntString(PyObject *p, const char *key, int val) {
   Py_DECREF(i);
   return retval;
 }
-
-int unzip(PyObject *iterator, const int len, BarObject *bars[], double val[]) {
-  if (!PyIter_Check(iterator)) {
-    PyErr_SetString(PyExc_TypeError, "object not iterable");
-    return -1;
-  }
-
-  PyObject *item;
-  int index = 0;
-  while ((item = PyIter_Next(iterator)) && (index < len)) {
-    if (!PyTuple_Check(item) || PyTuple_Size(item) != 2) {
-      PyErr_SetString(PyExc_TypeError, "item must be two element tuple");
-      Py_DECREF(item);
-      return -1;
-    }
-
-    PyObject *bo, *vo;
-    if ((bo = PyTuple_GetItem(item, 0)) == NULL || (vo = PyTuple_GetItem(item, 1)) == NULL) {
-      PyErr_SetString(PyExc_RuntimeError, "unable to unpack tuple");
-      Py_DECREF(item);
-      return -1;
-    }
-
-    if (!PyObject_TypeCheck(bo, &BarType) || !PyFloat_Check(vo)) {
-      PyErr_SetString(PyExc_TypeError, "tuple must contain glpk.Bar and double");
-      Py_DECREF(item);
-      return -1;
-    }
-
-    index += 1;
-    bars[index] = (BarObject *) bo;
-    val[index] = PyFloat_AsDouble(vo);
-
-    Py_DECREF(item);
-  }
-
-  return index;
-}

tox.ini

@@ -10,5 +10,5 @@ skip_install = true
 setenv =
     CFLAGS=-coverage
 commands =
-    {envpython} setup.py clean --all install
+    {envpython} -m pip install .
     pytest