[LyX/master] improved data types for prefix length and pointer diff

[Stephan Witt]

commit dd6b5cc67cc641a49ad188e54018c6a1ffdbc017
Author: Stephan Witt <sw...@lyx.org>
Date:   Fri Nov 20 20:48:56 2015 +0100

    improved data types for prefix length and pointer diff

diff --git a/src/TexRow.cpp b/src/TexRow.cpp
index 37e5f64..8586a81 100644
--- a/src/TexRow.cpp
+++ b/src/TexRow.cpp
@@ -475,7 +475,7 @@ docstring TexRow::asString(RowEntry const & entry)
 ///prepends the texrow to the source given by tex, for debugging purpose
 void TexRow::prepend(docstring_list & tex) const
 {
-       int const prefix_length = 25;
+       size_type const prefix_length = 25;
        if (tex.size() < rowlist_.size())
                tex.resize(rowlist_.size());
        std::vector<RowEntryList>::const_iterator it = rowlist_.begin();
@@ -489,7 +489,7 @@ void TexRow::prepend(docstring_list & tex) const
                        entry += asString(*it2);
                if (entry.length() < prefix_length)
                        entry = entry + docstring(prefix_length - 
entry.length(), L' ');
-               int i = it - beg;
+               ptrdiff_t i = it - beg;
                tex[i] = entry + "  " + tex[i];
        }
 }