CMakeLists: use system zstd on Linux

From what I understand, this tells CMake to use the system, not conan,
version of zstd. Required to build on the coming MinGW Docker container.

src/common/CMakeLists.txt

@@ -192,4 +192,9 @@ create_target_directory_groups(common)
 find_package(Boost 1.71 COMPONENTS context headers REQUIRED)
 
 target_link_libraries(common PUBLIC ${Boost_LIBRARIES} fmt::fmt microprofile)
-target_link_libraries(common PRIVATE lz4::lz4 zstd xbyak)
+target_link_libraries(common PRIVATE lz4::lz4 xbyak)
+if (MSVC)
+  target_link_libraries(common PRIVATE zstd::zstd)
+else()
+  target_link_libraries(common PRIVATE zstd)
+endif()