Provide debugging symbols for releases

Occasionally I run into an issue where I get an exception in QtGUI4.dll in the release version of my software. Unfortunately, I do not have the debugging symbols for the build of Qt I am using so the stack trace isn't very informative. It would be fantastic if the debugging symbols for the release builds of the Qt libraries were available for download.

For Windows development, the symbols would be in the .PDB file:
.pro file addition:

win32 {

1. Turn on additional settings for building the Windows release
2. Zi Enable debugging info
   QMAKE_CFLAGS_RELEASE += /Zi

1. Turn on additional settings for linking the Windows release
2. DEBUG Create debug information
3. MAP Create memory map
4. OPT:REF Eliminate functions and/or data that are not referenced
5. OPT:ICF Perform identical COMDAT folding (identical code is only referenced once)
   QMAKE_LFLAGS_RELEASE += /DEBUG /MAP /OPT:REF /OPT:ICF
   }