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

fusl/src/complex/cargl.c

Index: fusl/src/complex/cargl.c
diff --git a/fusl/src/complex/cargl.c b/fusl/src/complex/cargl.c
new file mode 100644
index 0000000000000000000000000000000000000000..e0d504782f1fc36aa7fcb70a9e40248f7a9b4be4
--- /dev/null
+++ b/fusl/src/complex/cargl.c
@@ -0,0 +1,13 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double cargl(long double complex z)
+{
+	return carg(z);
+}
+#else
+long double cargl(long double complex z)
+{
+	return atan2l(cimagl(z), creall(z));
+}
+#endif