Add a "fork" of musl as //fusl.

fusl/src/fenv/fenv.c

+#include <fenv.h>
+
+/* Dummy functions for archs lacking fenv implementation */
+
+int feclearexcept(int mask)
+{
+        return 0;
+}
+
+int feraiseexcept(int mask)
+{
+        return 0;
+}
+
+int fetestexcept(int mask)
+{
+        return 0;
+}
+
+int fegetround(void)
+{
+        return FE_TONEAREST;
+}
+
+int __fesetround(int r)
+{
+        return 0;
+}
+
+int fegetenv(fenv_t *envp)
+{
+        return 0;
+}
+
+int fesetenv(const fenv_t *envp)
+{
+        return 0;
+}