Stop propagating std flags to downstream gcc/nvcc (pytorch#10098)

Summary:
When we directly use -std=c++11, it propagates to the downstream applications.

Problems:
1. Gcc flags propagating to nvcc.
2. nvcc flags propagating to nvcc. (Which throws an error like redeclaration of std flag)

This PR will fix these propagation issues!

Similar problem:
FloopCZ/tensorflow_cc#92
CGAL/cgal#2775

Requires: Cmake 3.12
Pull Request resolved: pytorch#10098

Differential Revision: D9187110

Pulled By: ezyang

fbshipit-source-id: 0e00e6aa3119c77a5b3ea56992ef3bbfecd71d80

Author: achalshah20

caffe2/CMakeLists.txt

@@ -223,7 +223,13 @@ target_include_directories(caffe2 PRIVATE ${Caffe2_CPU_INCLUDE})
 target_include_directories(caffe2 SYSTEM PRIVATE "${Caffe2_DEPENDENCY_INCLUDE}")
 # Set standard properties on the target
 aten_set_target_props(caffe2)
+
+if (MSVC)
 target_compile_options(caffe2 INTERFACE "-std=c++11")
+else()
+target_compile_options(caffe2 INTERFACE "$<$<COMPILE_LANGUAGE:CXX>:-std=c++11>")
+endif()
+
 target_compile_options(caffe2 PRIVATE "-DCAFFE2_BUILD_MAIN_LIB")
 if (MSVC AND NOT BUILD_SHARED_LIBS)
   # Note [Supporting both static and dynamic libraries on Window]

cmake/public/threads.cmake

@@ -5,14 +5,12 @@ if(THREADS_FOUND AND NOT TARGET Threads::Threads)
   add_library(Threads::Threads INTERFACE IMPORTED)
 
   if(THREADS_HAVE_PTHREAD_ARG)
-    set_property(
-        TARGET Threads::Threads
-        PROPERTY INTERFACE_COMPILE_OPTIONS "-pthread")
+    set_property(TARGET Threads::Threads
+                 PROPERTY INTERFACE_COMPILE_OPTIONS "-pthread")
   endif()
 
   if(CMAKE_THREAD_LIBS_INIT)
-    set_property(
-        TARGET Threads::Threads
-        PROPERTY INTERFACE_LINK_LIBRARIES "${CMAKE_THREAD_LIBS_INIT}")
+    set_property(TARGET Threads::Threads
+                 PROPERTY INTERFACE_LINK_LIBRARIES "${CMAKE_THREAD_LIBS_INIT}")
   endif()
-endif()
+endif()