Fixed file name comparisions by #include and FileInstall (non-compiled).

Differences are as described for lstrcmpi (old) and CompareStringOrdinal
with bIgnoreCase = true (new):
https://learn.microsoft.com/en-us/windows/win32/intl/handling-sorting-in-your-applications#sort-strings-ordinally

source/lib/file.cpp

@@ -531,7 +531,7 @@ static bool FileInstallCopy(LPCTSTR aSource, LPCTSTR aDest, bool aOverwrite)
 	SetCurrentDirectory(g_script.mFileDir);
 	GetFullPathName(aSource, _countof(source_path), source_path, NULL);
 	SetCurrentDirectory(g_WorkingDir); // Restore to proper value.
-	if (!lstrcmpi(source_path, dest_path) // Full paths are equal.
+	if (!ostrcmpi(source_path, dest_path) // Full paths are equal.
 		&& !(GetFileAttributes(source_path) & FILE_ATTRIBUTE_DIRECTORY)) // Source file exists and is not a directory (otherwise, an error should be thrown).
 		return true;
 

source/script.cpp

@@ -1559,7 +1559,7 @@ ResultType Script::OpenIncludedFile(TextStream *&ts, LPCTSTR aFileSpec, bool aAl
 		// to support automatic "include once" behavior.  So just ignore repeats:
 		if (!aAllowDuplicateInclude)
 			for (int f = 0; f < source_file_index; ++f) // Here, source_file_index==Line::sSourceFileCount
-				if (!lstrcmpi(Line::sSourceFile[f], full_path)) // Case insensitive like the file system (testing shows that "Ä" == "ä" in the NTFS, which is hopefully how lstrcmpi works regardless of locale).
+				if (!ostrcmpi(Line::sSourceFile[f], full_path)) // Case insensitive like the file system (e.g. "Ä" == "ä" in the NTFS).
 					return OK;
 		// The path is copied into persistent memory further below, after the file has been opened,
 		// in case the opening fails and aIgnoreLoadFailure==true.  Initialize for the check below.

source/util.h

@@ -595,6 +595,10 @@ int FTOA(double aValue, LPTSTR aBuf, int aBufSize);
 // returns 0 on failure, but failure occurs only when parameter/flag is invalid, which should never happen in
 // this case.
 #define lstrcmpni(str1, len1, str2, len2) (CompareString(LOCALE_USER_DEFAULT, NORM_IGNORECASE, str1, (int)(len1), str2, (int)(len2)) - 2) // -2 for maintainability
+// Compare string using the operating system uppercasing table, independent of locale but treating non-ASCII
+// letters such as è and È as equivalent.  Documentation indicates it will be consistent with NTFS file names.
+#define ostrcmpni(str1, len1, str2, len2) (CompareStringOrdinal(str1, (int)(len1), str2, (int)(len2), TRUE) - 2) // -2 for maintainability
+#define ostrcmpi(str1, str2) (ostrcmpni(str1, -1, str2, -1))
 
 
 // The following macros simplify and make consistent the calls to MultiByteToWideChar().