Sorry, been for a short holiday in New Zealand

The -I option sets paths to search for include files, not a wildcard list of dynamically loaded library files. Similarly, the -L options sets paths for the linker to search when looking for library files (libjpeg.a and/or libjpeg.so) during linking.

Assuming that the updated JPEG library files are installed into /usr/local/include, /usr/local/lib etc then:
Qt Code: 
  1. ./configure -I/usr/local/include -L/usr/local/lib
To copy to clipboard, switch view to plain text mode 
should do it.

Rpath is documented in the linker manual page:
Qt Code: 
  1. man ld
To copy to clipboard, switch view to plain text mode 
Neither of the configure options controls how the dynamically loaded library (libjpeg.so in this case) is found at runtime: rpath has some impact on this. Using rpath is frowned upon because it makes adapting your software to other environments more difficult: rpath is typically given more weight than the user's environment (LD_LIBRARY_PATH). See also http://en.wikipedia.org/wiki/Rpath_%28linking%29