Issues #3167, #3682: tests for math.log and math.log10 were failing on

Solaris and OpenBSD.  Fix this by handling special values and domain
errors directly in mathmodule.c, passing only positive nonspecial floats
to the system log/log10.

Misc/NEWS

@@ -160,6 +160,9 @@ C-API
 Extension Modules
 -----------------
 
+- Issues #3167, #3682: Fix test_math failures for log, log10 on Solaris,
+  OpenBSD.
+
 - Issue #4365: Add crtassem.h constants to the msvcrt module.
 
 - Issue #4396: The parser module now correctly validates the with statement.

Modules/mathmodule.c

@@ -136,6 +136,58 @@ m_atan2(double y, double x)
 	return atan2(y, x);
 }
 
+/*
+    Various platforms (Solaris, OpenBSD) do nonstandard things for log(0),
+    log(-ve), log(NaN).  Here are wrappers for log and log10 that deal with
+    special values directly, passing positive non-special values through to
+    the system log/log10.
+ */
+
+static double
+m_log(double x)
+{
+	if (Py_IS_FINITE(x)) {
+		if (x > 0.0)
+			return log(x);
+		errno = EDOM;
+		if (x == 0.0)
+			return -Py_HUGE_VAL; /* log(0) = -inf */
+		else
+			return Py_NAN; /* log(-ve) = nan */
+	}
+	else if (Py_IS_NAN(x))
+		return x; /* log(nan) = nan */
+	else if (x > 0.0)
+		return x; /* log(inf) = inf */
+	else {
+		errno = EDOM;
+		return Py_NAN; /* log(-inf) = nan */
+	}
+}
+
+static double
+m_log10(double x)
+{
+	if (Py_IS_FINITE(x)) {
+		if (x > 0.0)
+			return log10(x);
+		errno = EDOM;
+		if (x == 0.0)
+			return -Py_HUGE_VAL; /* log10(0) = -inf */
+		else
+			return Py_NAN; /* log10(-ve) = nan */
+	}
+	else if (Py_IS_NAN(x))
+		return x; /* log10(nan) = nan */
+	else if (x > 0.0)
+		return x; /* log10(inf) = inf */
+	else {
+		errno = EDOM;
+		return Py_NAN; /* log10(-inf) = nan */
+	}
+}
+
+
 /*
    math_1 is used to wrap a libm function f that takes a double
    arguments and returns a double.
@@ -758,11 +810,11 @@ math_log(PyObject *self, PyObject *args)
 	if (!PyArg_UnpackTuple(args, "log", 1, 2, &arg, &base))
 		return NULL;
 
-	num = loghelper(arg, log, "log");
+	num = loghelper(arg, m_log, "log");
 	if (num == NULL || base == NULL)
 		return num;
 
-	den = loghelper(base, log, "log");
+	den = loghelper(base, m_log, "log");
 	if (den == NULL) {
 		Py_DECREF(num);
 		return NULL;
@@ -781,7 +833,7 @@ If the base not specified, returns the natural logarithm (base e) of x.");
 static PyObject *
 math_log10(PyObject *self, PyObject *arg)
 {
-	return loghelper(arg, log10, "log10");
+	return loghelper(arg, m_log10, "log10");
 }
 
 PyDoc_STRVAR(math_log10_doc,