Static linkage (#1377)

Fixes #1300

src/main/CMakeLists.txt

@@ -9,10 +9,20 @@ target_compile_features(clio PUBLIC cxx_std_23)
 add_executable(clio_server)
 target_sources(clio_server PRIVATE Main.cpp)
 target_link_libraries(clio_server PRIVATE clio)
-target_link_options(
-  # For now let's assume that we only using libstdc++ under gcc.
-  #
-  # TODO: libc++ static linkage in https://github.com/XRPLF/clio/issues/1300
-  clio_server PRIVATE $<$<AND:$<BOOL:${is_gcc}>,$<NOT:$<BOOL:${san}>>>:-static-libstdc++ -static-libgcc>
-)
+
+if (static)
+  target_link_options(clio_server PRIVATE -static)
+
+  if (is_gcc AND NOT san)
+    target_link_options(
+      # For now let's assume that we only using libstdc++ under gcc.
+      clio_server PRIVATE -static-libstdc++ -static-libgcc
+    )
+  endif ()
+
+  if (is_appleclang)
+    message(FATAL_ERROR "Static linkage not supported on AppleClang")
+  endif ()
+endif ()
+
 set_target_properties(clio_server PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})