Modifications to LGPL code, am I documenting it correctly?

Question

I'm using a modified version of Botan from the Qt Creator 2.0 sources. The standard Botan distribution is under a FreeBSD license, and Qt Creator 2.0 is under LGPL (which means that version of Botan is under LGPL? or at least the 3 files Nokia added are?). If I remember correctly, according to the LGPL, if I change an LGPL licensed work, I must re-release it under LGPL, and document all changes made and when, and make the full source available.

My changes consist of deleting one line of code in the .pro file and replacing it with this:

# 2010-08-10
# Removed reference to qtcreatorlibrary.pri since this is not being used in Qt Creator
# Added destination directory for compatibility with our build process
DESTDIR = ../lib

# Added this...
macx {
    # Necessary for macdeployqt to work (DESTDIR must also end in /lib)
    CONFIG += absolute_library_soname
    target.path = $$OUT_PWD/$$DESTDIR
    INSTALLS += target
}

I also intend to include a readme.txt file with the sources saying:

NOTE: This version of Botan is taken from the Qt Creator 2.0 (LGPL 2.1) sources, which has a few modifications by Nokia to integrate it with the qmake build system. We have also made some modifications of our own...

2010-08-10
Made a small modification to src/src.pro for better integration with our build processes, see the file (lines 6-17) for details

Are these notices sufficient?

Also, what additional notices must/should I place in my application's accompanying documentation besides the original Botan license and a note saying "The distribution of Botan used is Nokia's version of Botan 1.8.8 found in the Qt Creator 2.0 sources (LGPL 2.1) with a very small modification to the build file (but not the Botan code itself). See our Botan source package for details."

Answer 1

"If I remember correctly, according to the LGPL, if I change an LGPL licensed work, I must re-release it under LGPL, and document all changes made and when, and make the full source available."

You only need to release the modified source code if you distribute the library, and you can then use either the LGPL or the GPL. As far as I can see, you haven't even modified the source code, but merely adapted the build process to suit your needs.

The LGPL states absolutely no need to document the changes made, you just have to provide installation information.

In your case, simply include the LGPL and "give prominent notice with each copy of the Combined Work that the Library is used in it and that the Library and its use are covered by this License", as stated in 4.e. of the LGPL and don't forget that you have to "use a suitable shared library mechanism for linking with the Library", as stated in 4.d.1.

In a nutshell: your suggested notice is more than sufficient.

EDIT: You can always contact the FSF at [email protected] with your questions about the (L)GPL.