fix function signatures for parity with native functions in PHP 8

Author: xabbuh

src/Iconv/bootstrap80.php

@@ -59,22 +59,22 @@ function iconv_mime_decode($string, $mode = 0, $encoding = null) { $currentMbEnc
 } else {
     if (!function_exists('iconv_strlen')) {
         if (extension_loaded('xml')) {
-            function iconv_strlen(?string $string, ?string $encoding = null): int|false { return p\Iconv::strlen1((string) $string, $encoding); }
+            function iconv_strlen(string $string, ?string $encoding = null): int|false { return p\Iconv::strlen1((string) $string, $encoding); }
         } else {
-            function iconv_strlen(?string $string, ?string $encoding = null): int|false { return p\Iconv::strlen2((string) $string, $encoding); }
+            function iconv_strlen(string $string, ?string $encoding = null): int|false { return p\Iconv::strlen2((string) $string, $encoding); }
         }
     }
 
     if (!function_exists('iconv_strpos')) {
-        function iconv_strpos(?string $haystack, ?string $needle, ?int $offset = 0, ?string $encoding = null): int|false { return p\Iconv::iconv_strpos((string) $haystack, (string) $needle, (int) $offset, $encoding); }
+        function iconv_strpos(string $haystack, string $needle, int $offset = 0, ?string $encoding = null): int|false { return p\Iconv::iconv_strpos((string) $haystack, (string) $needle, (int) $offset, $encoding); }
     }
     if (!function_exists('iconv_strrpos')) {
-        function iconv_strrpos(?string $haystack, ?string $needle, ?string $encoding = null): int|false { return p\Iconv::iconv_strrpos((string) $haystack, (string) $needle, $encoding); }
+        function iconv_strrpos(string $haystack, string $needle, ?string $encoding = null): int|false { return p\Iconv::iconv_strrpos((string) $haystack, (string) $needle, $encoding); }
     }
     if (!function_exists('iconv_substr')) {
-        function iconv_substr(?string $string, ?int $offset, ?int $length = null, ?string $encoding = null): string|false { return p\Iconv::iconv_substr((string) $string, (string) $offset, $length, $encoding); }
+        function iconv_substr(string $string, int $offset, ?int $length = null, ?string $encoding = null): string|false { return p\Iconv::iconv_substr((string) $string, (string) $offset, $length, $encoding); }
     }
     if (!function_exists('iconv_mime_decode')) {
-        function iconv_mime_decode(?string $string, ?int $mode = 0, ?string $encoding = null): string|false { return p\Iconv::iconv_mime_decode((string) $string, (int) $mode, $encoding); }
+        function iconv_mime_decode(string $string, int $mode = 0, ?string $encoding = null): string|false { return p\Iconv::iconv_mime_decode((string) $string, (int) $mode, $encoding); }
     }
 }