Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -111,6 +111,8 @@
 option(LIBCXXABI_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
 option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
 option(LIBCXXABI_ENABLE_THREADS "Build with threads enabled" ON)
+set(LIBCXXABI_GCC_TOOLCHAIN "" CACHE STRING "GCC toolchain for cross compiling.")
+set(LIBCXXABI_SYSROOT "" CACHE STRING "Sysroot for cross compiling.")
 
 # Default to building a shared library so that the default options still test
 # the libc++abi that is being built. There are two problems with testing a
@@ -245,6 +247,11 @@
   add_definitions(-D_CRT_SECURE_NO_WARNINGS)
 endif()
 
+list(APPEND LIBCXXABI_COMPILE_FLAGS "-target ${LIBCXXABI_TARGET_TRIPLE}")
+append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_GCC_TOOLCHAIN
+         "-gcc-toolchain ${LIBCXXABI_GCC_TOOLCHAIN}")
+append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_SYSROOT
+          "--sysroot ${LIBCXXABI_SYSROOT}")
 string(REPLACE ";" " " LIBCXXABI_CXX_FLAGS "${LIBCXXABI_CXX_FLAGS}")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LIBCXXABI_CXX_FLAGS}")