Introduce SOVERSION for ABI compatibility (#771)

This commit sets the library's SOVERSION to its major version number.

Setting the soname this way establishes a clear ABI promise. This allows
users to safely upgrade to minor or patch releases without needing to
recompile their applications, as long as the major version remains the
same.

CMakeLists.txt

@@ -16,11 +16,13 @@ if(NOT ADS_VERSION)
     string(REGEX REPLACE "^[0-9]+\\.([0-9]+).*" "\\1" VERSION_MINOR "${GitTagVersion}")
     string(REGEX REPLACE "^[0-9]+\\.[0-9]+\\.([0-9]+).*" "\\1" VERSION_PATCH "${GitTagVersion}")
     set(VERSION_SHORT "${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH}")
+    set(VERSION_SONAME "${VERSION_MAJOR}")
 else()
     string(REGEX MATCHALL "[\.]" VERSION_DOT_MATCHES ${ADS_VERSION})
     list(LENGTH VERSION_DOT_MATCHES VERSION_DOT_COUNT)
     if(VERSION_DOT_COUNT EQUAL 2)
         set(VERSION_SHORT ${ADS_VERSION})
+        string(REGEX REPLACE "^([0-9]+)\\..*" "\\1" VERSION_SONAME "${ADS_VERSION}")
     else()
         message(FATAL_ERROR "ADS_VERSION must be in major.minor.patch format, e.g. 3.8.1. Got ${ADS_VERSION}")
     endif()

src/CMakeLists.txt

@@ -109,6 +109,7 @@ set_target_properties(${library_name} PROPERTIES
     AUTORCC ON
     CXX_EXTENSIONS OFF
     VERSION ${VERSION_SHORT}
+    SOVERSION ${VERSION_SONAME}
     EXPORT_NAME ${library_name}
     DEBUG_POSTFIX "d"
     ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${ads_PlatformDir}/lib"