The postgresql library -lpq depends on -lsecure32, -lssl, and so
on. These are static libraries. When we build the psql plugin as
a shared library, linking fails unless we provide the list of
required libraries.
Previously, this was taken care of with a hack in the configure
script. Since that hack is not suitable for an upstream merge
request, I have moved it here.
We have been building Qt with "-openssl-linked". A patch was needed to adjust
OPENSSL_LIBS to keep a shared Qt build from failing at the point where
QtNetwork4.dll is linked. The patch is not needed if we use "-openssl" instead.
Because libssl and its dependencies are static libraries in mingw-cross-env,
a simple "-openssl" also causes libssl and dependencies to be embedded
(imported) into QNetwork4.dll, but it does so without requiring the patch.
Details:
The patch solved a problem that is a feature of a specific recipe of
Qt build ingredients:
(1) -shared
(2) -openssl-linked
(3) -qt-zlib
in an environment were:
(4) openssl is static
(5) “system” zlib is static
At least 1-3 are needed to see the problem. I suspect that 4 and 5 are needed as
well.
What I think I understand:
“-shared” means that QtNetwork4.dll will be built, which is the locus of the
problem.
“-openssl-linked” means that libssl and its dependencies are to be embedded in
QtNetwork4.dll. OPENSSL_LIBS supplies the list of dependencies.
“-qt-zlib” means that QtCore4 contains a zlib implementation.
Given this recipe for QtNetwork4.dll, the zlib implementation of “-lz” conflicts
with the zlib implementation of “-lQtCore4”.
The patch removed "-lz" from OPENSSL_LIBS and replaced it with "-lQtCore" in the
same position. Adding "-lQtCore" in this way is not a robust solution. For example,
it will break a debug build.
* support for postgresql, tds and openssl
* fixed detection for float, zlib, libjpeg, libtiff, libmng,
libpng, postgresql, tds, sqlite, iconv,
STL, IPv6 and openssl
* added "-pipe" to CFLAGS to speed up build
Volker Grabsch
Mark Brand