string: fix to compile with Xcode

Signed-off-by: Simon Rozman <simon@rozman.si>

include/stdex/string.hpp

@@ -1,4 +1,4 @@
-/*
+/*
 	SPDX-License-Identifier: MIT
 	Copyright © 2016-2025 Amebis
 */
@@ -1107,6 +1107,7 @@ namespace stdex
 		return 0;
 	}
 
+#ifdef _WIN32
 	///
 	/// Binary compare two strings
 	///
@@ -1125,6 +1126,7 @@ namespace stdex
 			reinterpret_cast<const utf16_t*>(str1), count1,
 			reinterpret_cast<const utf16_t*>(str2), count2);
 	}
+#endif
 
 	///
 	/// Binary compare two strings
@@ -1142,6 +1144,7 @@ namespace stdex
 		return strncmp(str1, N1, str2, N2);
 	}
 
+#ifdef _WIN32
 	///
 	/// Binary compare two strings
 	///
@@ -1159,6 +1162,7 @@ namespace stdex
 			reinterpret_cast<const utf16_t*>(str1), N1,
 			reinterpret_cast<const utf16_t*>(str2), N2);
 	}
+#endif
 
 	///
 	/// Binary compare two strings in reverse direction