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

fusl/src/math/fdiml.c

Index: fusl/src/math/fdiml.c
diff --git a/fusl/src/math/fdiml.c b/fusl/src/math/fdiml.c
new file mode 100644
index 0000000000000000000000000000000000000000..62e29b7df39e1cb25e73b844cbb98e423bf87d26
--- /dev/null
+++ b/fusl/src/math/fdiml.c
@@ -0,0 +1,18 @@
+#include <math.h>
+#include <float.h>
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double fdiml(long double x, long double y)
+{
+	return fdim(x, y);
+}
+#else
+long double fdiml(long double x, long double y)
+{
+	if (isnan(x))
+		return x;
+	if (isnan(y))
+		return y;
+	return x > y ? x - y : 0;
+}
+#endif