backporting: remove redefinition of strconv__Float64u

vlib/strconv/structs.v

@@ -0,0 +1,49 @@
+module strconv
+
+// The structure is filled by parser, then given to converter.
+pub struct PrepNumber {
+pub mut:
+	negative bool // 0 if positive number, 1 if negative
+	exponent int // power of 10 exponent
+	mantissa u64 // integer mantissa
+}
+
+// dec32 is a floating decimal type representing m * 10^e.
+struct Dec32 {
+mut:
+	m u32
+	e int
+}
+
+// dec64 is a floating decimal type representing m * 10^e.
+struct Dec64 {
+mut:
+	m u64
+	e int
+}
+
+struct Uint128 {
+mut:
+	lo u64
+	hi u64
+}
+
+// support union for convert f32 to u32
+union Uf32 {
+mut:
+	f f32
+	u u32
+}
+
+// support union for convert f64 to u64
+union Uf64 {
+mut:
+	f f64
+	u u64
+}
+
+union Float64u {
+mut:
+	f f64
+	u u64
+}