Fix OpenBSD build

LLVM 19.1 doesn't have from_chars for double.

CMakeLists.txt

@@ -5,7 +5,7 @@ project(asciicast2webp VERSION 0.1 DESCRIPTION "Render asciicast as WebP"
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(LIBRARIES REQUIRED
     vterm cairo libwebp libwebpmux libjq oniguruma)
-pkg_search_module(TERMINFO REQUIRED tinfo ncursesw)
+pkg_search_module(TERMINFO REQUIRED tinfo ncursesw ncurses)
 
 add_executable(${PROJECT_NAME} ${PROJECT_NAME}.cpp)
 target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_20)

asciicast2webp.cpp

@@ -23,7 +23,7 @@
 #include <clocale>
 #include <cmath>
 #include <cstdint>
-#include <cstring>
+#include <cstdlib>
 #include <filesystem>
 #include <fstream>
 #include <iostream>
@@ -1369,22 +1369,22 @@ void usage(const char *program) {
 
 int parse_integer_option(
 	const char *name, const char *value, int minimum, int maximum) {
-	int result = 0;
-	const char *end = value + strlen(value);
-	const auto [position, error] = from_chars(value, end, result);
-	if (error != errc{} || position != end || result < minimum ||
+	char *end = nullptr;
+	errno = 0;
+	const long result = strtol(value, &end, 10);
+	if (errno == ERANGE || end == value || *end || result < minimum ||
 		result > maximum) {
 		fail(string(name) + " must be between " + to_string(minimum) + " and " +
 			to_string(maximum));
 	}
-	return result;
+	return int(result);
 }
 
 double parse_real_option(const char *name, const char *value) {
-	double result = 0.;
-	const char *end = value + strlen(value);
-	const auto [position, error] = from_chars(value, end, result);
-	if (error != errc{} || position != end || !isfinite(result))
+	char *end = nullptr;
+	errno = 0;
+	const double result = strtod(value, &end);
+	if (errno == ERANGE || end == value || *end || !isfinite(result))
 		fail(string(name) + " must be a finite number");
 	return result;
 }