Use C++20 concepts to require constraints on template parameters (#1977)

src/gfx/pal_spec.cpp

@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <array>
 #include <charconv>
+#include <concepts> // unsigned_integral
 #include <errno.h>
 #include <fstream>
 #include <inttypes.h>
@@ -202,7 +203,7 @@ static void warnExtraColors(
 }
 
 // Parses the initial part of a string_view, advancing the "read index" as it does
-template<typename UintT> // Should be uint*_t
+template<std::unsigned_integral UintT>
 static std::optional<UintT> parseDec(std::string const &str, size_t &n) {
 	UintT value = 0;
 	auto result = std::from_chars(str.data() + n, str.data() + str.length(), value);