converted formafractional_part_rounding_thresholds to use an array of u32s instead of a unicode literal character array for compatibliity with CUDA and non CUDA platforms

Author: Cazadorro

include/fmt/format.h

@@ -3208,15 +3208,22 @@ FMT_CONSTEXPR20 void format_hexfloat(Float value, format_specs specs,
   format_hexfloat(static_cast<double>(value), specs, buf);
 }
 
+// pre C++23 does not allow static constexpr inside of constexpr functions
+// so we must declare this outside of fractional_part_rounding_thresholds
+static constexpr uint32_t utf8_raw_rounding_thresholds[8] = {
+  0x9999999au, 0x828f5c29u, 0x80418938u, 0x80068db9,
+  0x8000a7c6u, 0x800010c7u, 0x800001aeu, 0x8000002bu
+};
+
 constexpr auto fractional_part_rounding_thresholds(int index) -> uint32_t {
   // For checking rounding thresholds.
   // The kth entry is chosen to be the smallest integer such that the
   // upper 32-bits of 10^(k+1) times it is strictly bigger than 5 * 10^k.
   // It is equal to ceil(2^31 + 2^32/10^(k + 1)).
   // These are stored in a string literal because we cannot have static arrays
   // in constexpr functions and non-static ones are poorly optimized.
-  return U"\x9999999a\x828f5c29\x80418938\x80068db9\x8000a7c6\x800010c7"
-         U"\x800001ae\x8000002b"[index];
+
+  return utf8_raw_rounding_thresholds[index];
 }
 
 template <typename Float>