Fix unicode filename compare when wchar_t is not 16bit

Do not use wcscmp() which takes wchar_t arguments.
wchar_t bit width is system dependent. It is often 32bits.
Grafx2 supports 16bits wide characters

fixes b49fa1dfcc6209065c79f112b364a75f0d30e2b2

src/filesel.c

@@ -827,7 +827,7 @@ void Read_list_of_drives(T_Fileselector *list, byte name_length)
 #else
 // case-sensitive
   #define FILENAME_COMPARE strcmp
-  #define FILENAME_COMPARE_UNICODE wcscmp
+  #define FILENAME_COMPARE_UNICODE Unicode_strcmp
 #endif
 
 

src/unicode.c

@@ -73,6 +73,18 @@ void Unicode_strlcat(word * dst, const word * src, size_t len)
   Unicode_strlcpy(dst + dst_len, src, len - dst_len);
 }
 
+/// Compare two unicode strings
+int Unicode_strcmp(const word * s1, const word * s2)
+{
+  while (*s1 == *s2)
+  {
+    if (*s1 == 0) return 0;
+    s1++;
+    s2++;
+  }
+  return (*s1 > *s2) ? 1 : -1;
+}
+
 /// Compare an unicode string with a regular Latin1 string
 int Unicode_char_strcmp(const word * s1, const char * s2)
 {

src/unicode.h

@@ -46,6 +46,9 @@ void Unicode_strlcpy(word * dst, const word * src, size_t len);
 /// Append unicode string to another
 void Unicode_strlcat(word * dst, const word * src, size_t len);
 
+/// Compare two unicode strings
+int Unicode_strcmp(const word * s1, const word * s2);
+
 /// Compare an unicode string with a regular Latin1 string
 int Unicode_char_strcmp(const word * s1, const char * s2);