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

fusl/src/math/roundf.c

Index: fusl/src/math/roundf.c
diff --git a/fusl/src/math/roundf.c b/fusl/src/math/roundf.c
new file mode 100644
index 0000000000000000000000000000000000000000..e8210af5621aa392543616d308200ddb22523281
--- /dev/null
+++ b/fusl/src/math/roundf.c
@@ -0,0 +1,36 @@
+#include "libm.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 roundf(float x)
+{
+	union {float f; uint32_t i;} u = {x};
+	int e = u.i >> 23 & 0xff;
+	float_t y;
+
+	if (e >= 0x7f+23)
+		return x;
+	if (u.i >> 31)
+		x = -x;
+	if (e < 0x7f-1) {
+		FORCE_EVAL(x + toint);
+		return 0*u.f;
+	}
+	y = x + toint - toint - x;
+	if (y > 0.5f)
+		y = y + x - 1;
+	else if (y <= -0.5f)
+		y = y + x + 1;
+	else
+		y = y + x;
+	if (u.i >> 31)
+		y = -y;
+	return y;
+}