[libpq] Add support for dynamic builds with Visual Studio

[Talkless]

• Fix source file lists to avoid link errors and to behave be as close as possible to the original MSVC projects.
• Generate more complete pg_config.h.
• Use .def file to make exported symbols work as expected.
• Add missing wldap32 library link in package_info().
• Enable dynamc build in conanfile.py

Specify library name and version: libpq/11.5

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

Original related bug report: bincrafters/conan-libpq#25

[conan-center-bot]

Sorry, the build is only launched for Early Access Program users. You can request access writing in this issue.

[Talkless]

I have issue - test_package.exe application fails because it for some reason expects libpqd.dll, while libpq is build without d suffix.

Interestingly, in the official Qt builds, qsqlpsqld.dll plugin still requires libpq.dll (without d). And if I specifcy build_type=Release in my profile.txt, test_package.exe still requires libpqd.dll?

[Talkless]

OK the issue seems is here:

    if (CMAKE_BUILD_TYPE EQUAL Debug)
        set(DLL_DEF_FILE source_subfolder/src/interfaces/libpq/libpqddll.def)
    else()
        set(DLL_DEF_FILE source_subfolder/src/interfaces/libpq/libpqdll.def)
    endif()

Looks like conan does not set CMAKE_BUILD_TYPE, so either always release .def file is used, or if I change if() logic, always debug .def file is used, so one of the test_package.exe builds fails to find libpq[d].dll. It either always wants libpq.dll or libpqd.dll...

How do I detect build_type=Release|Debug in CMakeLists.txt? @uilianries, anywone?

[Talkless]

Looks like I have to use generator expressions? Though using add_library(libpq ${pg_port_src} ${pg_backend_src} ${pg_libpq_src} ${DLL_DEF_FILE} "$<$<CONFIG:Debug>:${DLL_DEF_FILE_DEBUG}>" "$<$<CONFIG:Release>:${DLL_DEF_FILE_RELEASE}>") fails with:

-- Generating done
CMake Error in CMakeLists.txt:
  Target "libpq" has source files which vary by configuration.  This is not
  supported by the "Visual Studio 14 2015" generator.

[Talkless]

Started discussion in CMake bug tracker:
https://gitlab.kitware.com/cmake/cmake/issues/19782

I guess I'll just use libpqdll.def (without "d" suffix) for both debug and release builds, as I don't know alternative yet. Though this looks like deviation from upstream, as libpqddll.def hints that originally it should be libpqd.dll when built in debug mode...

[conan-center-bot]

Sorry, the build is only launched for Early Access Program users. You can request access writing in this issue.

[conan-center-bot]

Sorry, the build is only launched for Early Access Program users. You can request access writing in this issue.

[Talkless]

There are more issues to be fixed after this is merged, but I can't do anything without early access.

@SSE4 @uilianries could someone author this PR instead of me, to make thins more forward?

[SSE4]

@Talkless I'll create PR from my account and give you write permissions to my fork

[SSE4]

moved to #188