Compile and test code designated for the next ABI (#497)

Author: swebb2066

.github/workflows/log4cxx-ubuntu.yml

@@ -38,6 +38,7 @@ jobs:
             exitevents: OFF
             fuzzers: OFF
             logchar: utf-8
+            next_abi: OFF
           - name: ubuntu22-clang
             os: ubuntu-22.04
             cxx: clang++
@@ -50,6 +51,7 @@ jobs:
             exitevents: OFF
             fuzzers: ON
             logchar: utf-8
+            next_abi: OFF
           - name: ubuntu24-gcc
             os: ubuntu-24.04
             cxx: g++
@@ -62,6 +64,7 @@ jobs:
             exitevents: ON
             fuzzers: OFF
             logchar: utf-8
+            next_abi: ON
           - name: ubuntu24-clang
             os: ubuntu-24.04
             cxx: clang++
@@ -74,6 +77,7 @@ jobs:
             exitevents: OFF
             fuzzers: ON
             logchar: wchar_t
+            next_abi: OFF
 
     steps:
     - uses: actions/checkout@v4
@@ -113,6 +117,7 @@ jobs:
           -DLOG4CXX_EVENTS_AT_EXIT=${{ matrix.exitevents }} \
           -DBUILD_FUZZERS=${{ matrix.fuzzers }} \
           -DLOG4CXX_CHAR=${{ matrix.logchar }} \
+          -DLOG4CXX_BUILD_NEXT_ABI=${{ matrix.next_abi }} \
           ..
         cmake --build .
 

CMakeLists.txt

@@ -33,10 +33,12 @@ set(LOG4CXX_NS "log4cxx" CACHE STRING "Root namespace name")
 # Note that the lib version is different from the SOVERSION
 # The lib version is the version of log4cxx, the SOVERSION is the ABI version
 # See also: https://cmake.org/pipermail/cmake/2012-September/051904.html
-set(current_log4cxx_ABI_VER 15)
-set(next_log4cxx_ABI_VER 16)
-set(log4cxx_ABI_VER "${current_log4cxx_ABI_VER}" CACHE STRING "The DSO library version")
-set_property(CACHE log4cxx_ABI_VER PROPERTY STRINGS "${current_log4cxx_ABI_VER}" "${next_log4cxx_ABI_VER}")
+option(LOG4CXX_BUILD_NEXT_ABI "Build code designated for the next ABI version" OFF)
+if(LOG4CXX_BUILD_NEXT_ABI)
+  set(log4cxx_ABI_VER 16)
+else()
+  set(log4cxx_ABI_VER 15)
+endif()
 set(LIBLOG4CXX_LIB_VERSION ${log4cxx_ABI_VER}.${log4cxx_VERSION_MINOR}.${log4cxx_VERSION_PATCH})
 set(LIBLOG4CXX_LIB_SOVERSION ${log4cxx_ABI_VER})
 # Set the 'release' version.  This is the human-readable version