cmake: enable SOVERSION for Cygwin and `CMAKE_DLL_NAME_WITH_SOVERSION`

- enable SOVERSION when `CMAKE_DLL_NAME_WITH_SOVERSION=ON` is set.
  Ref: https://cmake.org/cmake/help/v3.27/variable/CMAKE_DLL_NAME_WITH_SOVERSION.html
  Use: https://github.com/search?q=-DCMAKE_DLL_NAME_WITH_SOVERSION&type=code

- enable SOVERSION for Cygwin builds by default.

Ref: #13936
Ref: #13944
Closes #13898

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index aedcfc6fdf0a66e5c733e385f74907955d174226..63e5b91390e0a43ff5f3e21ed89418c3abf07548 100644 (file)
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -191,7 +191,9 @@ if(BUILD_SHARED_LIBS)
     $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
     $<BUILD_INTERFACE:${CURL_SOURCE_DIR}/include>)
 
-  if(APPLE OR
+  if(CMAKE_DLL_NAME_WITH_SOVERSION OR
+    CYGWIN OR
+    APPLE OR
     CMAKE_SYSTEM_NAME STREQUAL "AIX" OR
     CMAKE_SYSTEM_NAME STREQUAL "Linux" OR
     CMAKE_SYSTEM_NAME STREQUAL "SunOS" OR