Fixed use of backslash in process commands.

src/process_win.cpp

@@ -98,10 +98,6 @@ Process::id_type Process::open(const std::string &command, const std::string &pa
 #ifdef MSYS_PROCESS_USE_SH
   size_t pos=0;
   std::string sh_command=command;
-  while((pos=sh_command.find('\\', pos))!=std::string::npos) {
-    sh_command.replace(pos, 1, "\\\\\\");
-    pos+=3;
-  }
   while((pos=sh_command.find('\"', pos))!=std::string::npos) {
     if(pos>0 && sh_command[pos-1]!='\\') {
       sh_command.replace(pos, 1, "\\\"");
@@ -109,6 +105,14 @@ Process::id_type Process::open(const std::string &command, const std::string &pa
     }
     pos++;
   }
+  pos=0;
+  while((pos=sh_command.find('\\', pos))!=std::string::npos) {
+    if((pos+1)==sh_command.size() || sh_command[pos+1]!='\"') {
+      sh_command.replace(pos, 1, "\\\\\\");
+      pos++;
+    }
+    pos+=2;
+  }
   sh_command.insert(0, "sh -c \"");
   sh_command+="\"";
   command_cstr=new char[sh_command.size()+1];