[LyX/2.1.x] Fix bugs 9190 and 9193.

[Enrico Forestieri]

commit 5f7948e5a52b7c6e375b5fbe676578a8b8117de0
Author: Enrico Forestieri <for...@lyx.org>
Date:   Mon Jul 28 00:33:13 2014 +0200

    Fix bugs 9190 and 9193.
    
    The conversion from floating point to string performed by
    boost:lexical_cast does not allow specifying a precision and,
    for example, values such as 0.9 are returned as 0.899999976.
    The standard C++ way for performing the conversion is using
    std::ostringstream which is exempt from this problem, even if
    less efficient. For the sake of accuracy, boost::lexical_cast
    is ditched in favor of the ostrinsgstream implementation.
    In C++11 another option would be using std::to_string, but I
    think it is not as efficient as the boost way and not worth
    implementing through #ifdef's.

diff --git a/src/support/convert.cpp b/src/support/convert.cpp
index 70cd91e..6b985f5 100644
--- a/src/support/convert.cpp
+++ b/src/support/convert.cpp
@@ -17,6 +17,7 @@
 #include <boost/lexical_cast.hpp>
 
 #include <string>
+#include <sstream>
 //needed for Mac OSX 10.5.2 Leopard
 #include <cstdlib>
 
@@ -106,14 +107,18 @@ docstring convert<docstring>(long l)
 template<>
 string convert<string>(float f)
 {
-       return lexical_cast<string>(f);
+       std::ostringstream val;
+       val << f;
+       return val.str();
 }
 
 
 template<>
 string convert<string>(double d)
 {
-       return lexical_cast<string>(d);
+       std::ostringstream val;
+       val << d;
+       return val.str();
 }
 
 
diff --git a/status.21x b/status.21x
index be981c2..e5b2cc3 100644
--- a/status.21x
+++ b/status.21x
@@ -87,6 +87,9 @@ What's new
 
 - Fix potential bug spotted by cppcheck.
 
+- Fix problems arising when converting floating point values to the
+  corresponding string representation (bugs 9190 and 9193).
+
 
 * DOCUMENTATION AND LOCALIZATION