Force the usage of the shared version of libzstd.

libzstd provides both flavors, and the current code favorites the static
version over the shared one.

In this patch we **force** the usage of the shared library, as should be
the case in Debian.

debian/changelog

@@ -2,6 +2,7 @@ qt6-base (6.4.2+dfsg-2) UNRELEASED; urgency=medium
 
   [ Lisandro Damián Nicanor Pérez Meyer ]
   * Update symbols files with buildd's logs.
+  * Force the usage of the shared version of libzstd (Closes: #1030546).
 
  -- Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>  Mon, 06 Feb 2023 14:35:39 -0300
 

debian/patches/force_shared_libzstd.patch

@@ -0,0 +1,28 @@
+Description: force the usage of the shared libzstd library.
+ The library provides both versions, and the original code prefers the static
+ version over the shared, while on Debian it should always use the shared
+ version.
+Author: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>
+Bug: https://bugreports.qt.io/browse/QTBUG-110978
+Forwarded: not-needed
+
+---
+ cmake/FindWrapZSTD.cmake |    7 ++-----
+ 1 file changed, 2 insertions(+), 5 deletions(-)
+
+--- a/cmake/FindWrapZSTD.cmake
++++ b/cmake/FindWrapZSTD.cmake
+@@ -25,11 +25,8 @@ include(FindPackageHandleStandardArgs)
+ if(TARGET zstd::libzstd_static OR TARGET zstd::libzstd_shared)
+     find_package_handle_standard_args(WrapZSTD
+                                       REQUIRED_VARS zstd_VERSION VERSION_VAR zstd_VERSION)
+-    if(TARGET zstd::libzstd_static)
+-        set(zstdtargetsuffix "_static")
+-    else()
+-        set(zstdtargetsuffix "_shared")
+-    endif()
++    set(zstdtargetsuffix "_shared")
++
+     if(NOT TARGET WrapZSTD::WrapZSTD)
+         add_library(WrapZSTD::WrapZSTD INTERFACE IMPORTED)
+         set_target_properties(WrapZSTD::WrapZSTD PROPERTIES

debian/patches/series

@@ -6,6 +6,7 @@ upstream_Add-M68k-detection.patch
 remove_privacy_breaches.diff
 build_path_embedded_qtbuildinternalsextra_cmake.patch
 cross.patch
+force_shared_libzstd.patch
 
 # Don't use yield on CPUs that might not support it
 armel-noyield.patch