[LyX/master] Fix #10858 compiler warnings.

[Richard Heck]

commit b954f478e31e640f292f865a5c41c65565e5c02a
Author: Richard Heck <rgh...@lyx.org>
Date:   Fri Dec 15 23:41:32 2017 -0500

    Fix #10858 compiler warnings.
---
 src/mathed/InsetMathHull.cpp |   16 +++++++---------
 src/support/gzstream.cpp     |    2 +-
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 892b9df..724c115 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -823,11 +823,9 @@ void InsetMathHull::preparePreview(DocIterator const & pos,
        for (idx_type idx = 0; idx < nargs(); ++idx)
                usedMacros(cell(idx), pos, macros, defs);
 
-       MacroNameSet::iterator it = defs.begin();
-       MacroNameSet::iterator end = defs.end();
        docstring macro_preamble;
-       for (; it != end; ++it)
-               macro_preamble.append(*it);
+       for (auto const & defit : defs)
+               macro_preamble.append(defit);
 
        // set the font series and size for this snippet
        DocIterator dit = pos.getInnerText();
@@ -1650,7 +1648,8 @@ void InsetMathHull::mutate(HullType newtype)
 
        default:
                // we passed the guard so we should not be here
-               LASSERT("Mutation not implemented, but should have been.", 
return);
+               LYXERR0("Mutation not implemented, but should have been.");
+               LASSERT(false, return);
                break;
        }// switch
 }
@@ -2084,11 +2083,10 @@ bool InsetMathHull::getStatus(Cursor & cur, FuncRequest 
const & cmd,
 
        case LFUN_LABEL_COPY_AS_REFERENCE: {
                bool enabled = false;
-               row_type row;
                if (cmd.argument().empty() && &cur.inset() == this) {
                        // if there is no argument and we're inside math, we 
retrieve
                        // the row number from the cursor position.
-                       row = (type_ == hullMultline) ? nrows() - 1 : cur.row();
+                       row_type row = (type_ == hullMultline) ? nrows() - 1 : 
cur.row();
                        enabled = numberedType() && label_[row] && 
numbered(row);
                } else {
                        // if there is an argument, find the corresponding 
label, else
@@ -2319,8 +2317,8 @@ bool InsetMathHull::readQuiet(Lexer & lex)
 int InsetMathHull::plaintext(odocstringstream & os,
         OutputParams const & op, size_t max_length) const
 {
-       // disables ASCII-art for export of equations. See #2275.
-       if (0 && display()) {
+       // Try enabling this now that there is a flag as requested at #2275.
+       if (buffer().isExporting() && display()) {
                Dimension dim;
                TextMetricsInfo mi;
                metricsT(mi, dim);
diff --git a/src/support/gzstream.cpp b/src/support/gzstream.cpp
index 521458e..22e7c07 100644
--- a/src/support/gzstream.cpp
+++ b/src/support/gzstream.cpp
@@ -121,7 +121,7 @@ int gzstreambuf::overflow( int c) { // used for output 
buffer only
     if ( ! ( mode & ios::out) || ! opened)
         return EOF;
     if (c != EOF) {
-        *pptr() = c;
+                               *pptr() = (char) c;
         pbump(1);
     }
     if ( flush_buffer() == EOF)