Minor tweaks for clang 12 compiles.

Clang 15.0.2 still isn't linking, though.
I get complaints, "ld: library not found for -lc++"

Author: James Barbetti

CMakeLists.txt

@@ -136,15 +136,21 @@ if (WIN32)
     SET(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
 elseif (APPLE)
     message("Target OS           : Mac OS X")
+    message("Target System Name    : ${CMAKE_HOST_SYSTEM_NAME}")
+    message("Target System Version : ${CMAKE_HOST_SYSTEM_VERSION}")
     # to be compatible back to Mac OS X 10.7
     if (DECENTTREE_FLAGS MATCHES "oldmac")
         add_definitions("-mmacosx-version-min=10.5")
         set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -mmacosx-version-min=10.5")
     elseif (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
         #Don't set --target parameter for Gnu C++ on MacOS
-    else()
+    elseif (CMAKE_HOST_SYSTEM_VERSION VERSION_LESS 20)
+        #Don't do this for MacOS BigSur or later
         add_definitions("--target=x86_64-apple-macos10.7")
         set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --target=x86_64-apple-macos10.7")
+    else()
+    add_definitions("--target=x86_64-apple-macos10.7")
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --target=x86_64-apple-macos10.8")
     endif()
     SET(CMAKE_FIND_LIBRARY_SUFFIXES .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
 elseif (UNIX)
@@ -249,6 +255,7 @@ elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     endif()
 
     # use libc++ per default in MacOS
+    # set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} -v")
     if (APPLE)
         SET(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LIBRARY "libc++")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
@@ -689,7 +696,8 @@ if (WIN32)
         set(PLATFORM_LIB "ws2_32")
     endif()
 else()
-    set(PLATFORM_LIB "m")
+    #This doesn't look to be needed for clang-15 builds
+    #set(PLATFORM_LIB "m")
 endif()
 
 if (DECENTTREE_FLAGS MATCHES "libcxx")

zlib-1.2.7/CMakeLists.txt

@@ -5,7 +5,7 @@ project(zlib C)
 
 if (APPLE)
     if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-        if ("${CMAKE_CXX_COMPILER_VERSION}" VERSION_GREATER "12")
+        if ("${CMAKE_CXX_COMPILER_VERSION}" VERSION_GREATER_EQUAL 13)
             set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-deprecated-non-prototype")
         endif()
     endif()