[compiler-rt][sanitizers] build ubsan, asan etc libraries with Mac Catalyst support

[thakis]

Summary

Like D118875, but for ubsan, asan, etc.

With this, I can successfully run:

bin/clang++ -target x86_64-apple-ios14.0-macabi foo.cc \
    -isysroot $(xcrun -show-sdk-path) -fsanitize=undefined

with a locally built libclang_rt.ubsan_osx_dynamic.dylib.

[thakis]

better

[hans]

lgtm

[thakis]

@delcypher This is another catalyst-related change that you probably have internally in some form.

compiler-rt/cmake/Modules/AddCompilerRT.cmake

foreach(libname ${libnames})
     endif()
 
     # Strip out -msse3 if this isn't macOS.
     set(target_flags ${LIB_CFLAGS})
     if(APPLE AND NOT "${libname}" MATCHES ".*\.osx.*")
       list(REMOVE_ITEM target_flags "-msse3")
     endif()
 
+    # Build the macOS sanitizers with Mac Catalyst support.
+    if (APPLE AND
+        "${COMPILER_RT_ENABLE_MACCATALYST}" AND
+        "${libname}" MATCHES ".*\.osx.*")
+      foreach(arch ${LIB_ARCHS_${libname}})
+        list(APPEND target_flags
+          -target ${arch}-apple-macos${DARWIN_osx_MIN_VER}
+          -darwin-target-variant ${arch}-apple-ios13.1-macabi)
+      endforeach()
+    endif()
+
     set_target_compile_flags(${libname}
       ${extra_cflags_${libname}} ${target_flags})
     set_property(TARGET ${libname} APPEND PROPERTY
       COMPILE_DEFINITIONS ${LIB_DEFS})
     set_target_properties(${libname} PROPERTIES FOLDER "Compiler-RT Libraries")
     if(APPLE)
       set_target_properties(${libname} PROPERTIES
         OSX_ARCHITECTURES "${LIB_ARCHS_${libname}}")
foreach(os ${LIB_OS})
         list(APPEND libnames ${libname})
         set(extra_cflags_${libname} ${DARWIN_${os}_CFLAGS} ${NO_LTO_FLAGS} ${NO_PGO_FLAGS} ${LIB_CFLAGS})
         set(output_name_${libname} ${libname}${COMPILER_RT_OS_SUFFIX})
         set(sources_${libname} ${LIB_SOURCES})
         format_object_libs(sources_${libname} ${os} ${LIB_OBJECT_LIBS})
         get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir_${libname})
         get_compiler_rt_install_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} install_dir_${libname})
       endif()
+
+      # Build the macOS sanitizers with Mac Catalyst support.
+      if ("${COMPILER_RT_ENABLE_MACCATALYST}" AND
+          "${os}" MATCHES "^(osx)$")
+        foreach(arch ${LIB_ARCHS_${libname}})
+          list(APPEND extra_cflags_${libname}
+            -target ${arch}-apple-macos${DARWIN_osx_MIN_VER}
+            -darwin-target-variant ${arch}-apple-ios13.1-macabi)
+          list(APPEND extra_link_flags_${libname}
+            -target ${arch}-apple-macos${DARWIN_osx_MIN_VER}
+            -darwin-target-variant ${arch}-apple-ios13.1-macabi)
+        endforeach()
+      endif()
     endforeach()
   else()
     foreach(arch ${LIB_ARCHS})
       if(NOT CAN_TARGET_${arch})
         message(FATAL_ERROR "Architecture ${arch} can't be targeted")
         return()
       endif()
       if(type STREQUAL "OBJECT")