vlib/math: Add a pure V backend for vlib/math (#11267)

vlib/math/sinh.c.v

@@ -0,0 +1,17 @@
+module math
+
+fn C.cosh(x f64) f64
+
+fn C.sinh(x f64) f64
+
+// cosh calculates hyperbolic cosine.
+[inline]
+pub fn cosh(a f64) f64 {
+	return C.cosh(a)
+}
+
+// sinh calculates hyperbolic sine.
+[inline]
+pub fn sinh(a f64) f64 {
+	return C.sinh(a)
+}