Fix MacOS compiling errors

cmake/CompileBoost.cmake

@@ -38,6 +38,10 @@ function(compile_boost)
   set(BOOST_LINK_FLAGS "")
   if(APPLE OR ICX OR USE_LIBCXX)
     list(APPEND BOOST_COMPILER_FLAGS -stdlib=libc++ -nostdlib++)
+    if (APPLE)
+      # Remove this after boost 1.81 or above is used
+      list(APPEND BOOST_COMPILER_FLAGS -D_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION)
+    endif()
     list(APPEND BOOST_LINK_FLAGS -lc++ -lc++abi)
     if (NOT APPLE)
       list(APPEND BOOST_LINK_FLAGS -static-libgcc)

cmake/ConfigureCompiler.cmake

@@ -79,6 +79,11 @@ if(WIN32)
   add_definitions(-D_USE_MATH_DEFINES) # Math constants
 endif()
 
+if(APPLE)
+# Remove this after boost 1.81 or above is used
+add_definitions(-D_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION)
+endif()
+
 if (USE_CCACHE)
   find_program(CCACHE_PROGRAM "ccache" REQUIRED)
   set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")

fdbmonitor/fdbmonitor.cpp

@@ -80,7 +80,9 @@
 #include "fdbclient/SimpleIni.h"
 #include "fdbclient/versions.h"
 
+#ifdef __linux__
 constexpr uint64_t DEFAULT_MEMORY_LIMIT = 8LL << 30;
+#endif
 constexpr double MEMORY_CHECK_INTERVAL = 2.0; // seconds
 
 #ifdef __linux__