build: detect correct folder in single-arch

On macOS, contrib outputs are placed under
<arch>-apple-darwin<ver> for single-arch builds and
under apple-darwin<ver> for multi-arch builds. Adjust
detection so the client picks the right include path.

Change-Id: Ia9ae2bb7b1f0d6e42cb15364b1921e94f2602836

CMakeLists.txt

@@ -441,12 +441,24 @@ set(COMMON_HEADERS
   ${APP_SRC_DIR}/qrcodescannermodel.h
   ${APP_SRC_DIR}/spellchecker.h)
 
+set(CONTRIB_DARWIN_FOLDER "")
+if(APPLE)
+  list(LENGTH CMAKE_OSX_ARCHITECTURES ARCH_LEN)
+  if(ARCH_LEN EQUAL 1)
+    # single-arch -> use <arch>-apple-darwin<ver>
+    set(DARWIN_ARCH "${CMAKE_OSX_ARCHITECTURES}")
+    set(CONTRIB_DARWIN_FOLDER "${DARWIN_ARCH}-apple-darwin${CMAKE_SYSTEM_VERSION}")
+  else() # multi-arch -> use apple-darwin<ver>
+    set(CONTRIB_DARWIN_FOLDER "apple-darwin${CMAKE_SYSTEM_VERSION}")
+  endif()
+endif()
+
 # For libavutil/avframe.
 set(LIBJAMI_CONTRIB_DIR "${DAEMON_DIR}/contrib")
 find_path(AVUTIL_INCLUDE_DIR libavutil/avutil.h
   PATHS
   ${LIBJAMI_CONTRIB_DIR}/native/ffmpeg
-  ${LIBJAMI_CONTRIB_DIR}/apple-darwin${CMAKE_SYSTEM_VERSION}/include/
+  ${LIBJAMI_CONTRIB_DIR}/${CONTRIB_DARWIN_FOLDER}/include/
   ${LIBJAMI_CONTRIB_DIR}/build/ffmpeg/Build/win32/x64/include)
 include_directories(${AVUTIL_INCLUDE_DIR})
 
@@ -934,7 +946,7 @@ else()
   target_sources(${PROJECT_NAME} PRIVATE ${resources})
   list(APPEND CLIENT_LIBS ${libs})
 
-  file(GLOB CONTRIB ${LIBJAMI_CONTRIB_DIR}/apple-darwin/lib/*.a)
+  file(GLOB CONTRIB ${LIBJAMI_CONTRIB_DIR}/${CONTRIB_DARWIN_FOLDER}/lib/*.a)
   list(APPEND CLIENT_LIBS ${CONTRIB})
 
   find_package(Iconv REQUIRED)