[LyX/master] Refine fix for #9453

[Enrico Forestieri]

commit 1af2242c7e9c3dd4edd1ddba5f65e5de5c5e600a
Author: Enrico Forestieri <for...@lyx.org>
Date:   Mon Mar 16 10:50:02 2015 +0100

    Refine fix for #9453
    
    It is better to introduce a dummy blank dir in TEXINPUTS rather than
    appending a blank at the end. Even if I have checked that this is not
    a problem with MikTeX, some other engine (maybe texlive, but I cannot
    check) could not ignore this space and take it as the name of a dir.
    In this case, TEXINPUTS would not end with an empty element and the
    standard search path would not be inserted there.

diff --git a/src/support/filetools.cpp b/src/support/filetools.cpp
index 229dd2e..1f794f2 100644
--- a/src/support/filetools.cpp
+++ b/src/support/filetools.cpp
@@ -733,10 +733,11 @@ string latexEnvCmdPrefix(string const & path)
                return "env TEXINPUTS=\"." + sep + texinputs_prefix
                                          + sep + texinputs + "\" ";
        else
-               // NOTE: *any* space in the last string matters! (see bug 9453)
-               return "cmd /d /c set \"TEXINPUTS=."
+               // NOTE: the dummy blank dir is necessary to force the
+               //       QProcess parser to quote the argument (see bug 9453)
+               return "cmd /d /c set \"TEXINPUTS=." + sep + " "
                                                + sep + texinputs_prefix
-                                               + sep + texinputs + " \" & ";
+                                               + sep + texinputs + "\" & ";
 }