cmcldeps: search for single-byte strings as characters

Source/cmcldeps.cxx

@@ -258,7 +258,7 @@ int main()
   // needed to suppress filename output of msvc tools
   std::string srcfilename;
   {
-    std::string::size_type pos = srcfile.rfind("\\");
+    std::string::size_type pos = srcfile.rfind('\\');
     if (pos == std::string::npos) {
       srcfilename = srcfile;
     } else {
@@ -280,7 +280,7 @@ int main()
     clrest = replace(clrest, objfile, objfile + ".dep.obj ");
 
     // rc: src\x\x.rc  ->  cl: /Tc src\x\x.rc
-    if (srcfile.find(" ") != std::string::npos)
+    if (srcfile.find(' ') != std::string::npos)
       srcfile = "\"" + srcfile + "\"";
     clrest = replace(clrest, srcfile, "/Tc " + srcfile);