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

fusl/src/math/rintf.c

Index: fusl/src/math/rintf.c
diff --git a/fusl/src/math/rintf.c b/fusl/src/math/rintf.c
new file mode 100644
index 0000000000000000000000000000000000000000..9047688d246a69c2698ce27399135e1db7ac2f65
--- /dev/null
+++ b/fusl/src/math/rintf.c
@@ -0,0 +1,30 @@
+#include <float.h>
+#include <math.h>
+#include <stdint.h>
+
+#if FLT_EVAL_METHOD==0
+#define EPS FLT_EPSILON
+#elif FLT_EVAL_METHOD==1
+#define EPS DBL_EPSILON
+#elif FLT_EVAL_METHOD==2
+#define EPS LDBL_EPSILON
+#endif
+static const float_t toint = 1/EPS;
+
+float rintf(float x)
+{
+	union {float f; uint32_t i;} u = {x};
+	int e = u.i>>23 & 0xff;
+	int s = u.i>>31;
+	float_t y;
+
+	if (e >= 0x7f+23)
+		return x;
+	if (s)
+		y = x - toint + toint;
+	else
+		y = x + toint - toint;
+	if (y == 0)
+		return s ? -0.0f : 0.0f;
+	return y;
+}