[NTOS] Make RtlFindCharInUnicodeString available in the kernel.

ntoskrnl/include/internal/rtl.h

@@ -22,4 +22,16 @@ RtlInitializeRangeListPackage(
     VOID
 );
 
+#define RTL_FIND_CHAR_IN_UNICODE_STRING_START_AT_END        1
+#define RTL_FIND_CHAR_IN_UNICODE_STRING_COMPLEMENT_CHAR_SET 2
+#define RTL_FIND_CHAR_IN_UNICODE_STRING_CASE_INSENSITIVE    4
+NTSTATUS
+NTAPI
+RtlFindCharInUnicodeString(
+    _In_ ULONG Flags,
+    _In_ PCUNICODE_STRING SearchString,
+    _In_ PCUNICODE_STRING MatchString,
+    _Out_ PUSHORT Position
+);
+
 /* EOF */