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

fusl/src/time/__month_to_secs.c

Index: fusl/src/time/__month_to_secs.c
diff --git a/fusl/src/time/__month_to_secs.c b/fusl/src/time/__month_to_secs.c
new file mode 100644
index 0000000000000000000000000000000000000000..43248fb3c519a009e3957ebbb1c219311fc61a49
--- /dev/null
+++ b/fusl/src/time/__month_to_secs.c
@@ -0,0 +1,10 @@
+int __month_to_secs(int month, int is_leap)
+{
+	static const int secs_through_month[] = {
+		0, 31*86400, 59*86400, 90*86400,
+		120*86400, 151*86400, 181*86400, 212*86400,
+		243*86400, 273*86400, 304*86400, 334*86400 };
+	int t = secs_through_month[month];
+	if (is_leap && month >= 2) t+=86400;
+	return t;
+}