CMakeLists.txt: set correct __cplusplus for MSVC

VC **always** sets __cplusplus to 199711L (sic!) unless passed
/Zc:__cplusplus for compat reasons. We now assume __cplusplus is at
least 201107L for C++ (in our case the CUDA code) for static_assert.

See also: <https://gitlab.kitware.com/cmake/cmake/-/issues/18837>

Author: MartinPulec

CMakeLists.txt

@@ -57,7 +57,7 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/")
 include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
 
 if(NOT MSVC OR MSVC_TOOLSET_VERSION GREATER 140)
-    list(APPEND NEEDED_COMPILER_FEATURES c_std_11)
+    set(NEEDED_COMPILER_FEATURES c_std_11)
 endif()
 
 set(COMPILED_OPTIONS)
@@ -74,6 +74,9 @@ endif()
 if (MSVC)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W4")
     set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler /W4")
+    if (MSVC_VERSION GREATER_EQUAL 1914)
+        set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler /Zc:__cplusplus")
+    endif()
 else()
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic")
     set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler -Wall -Xcompiler -Wextra")

src/gpujpeg_common_internal.h

@@ -46,7 +46,14 @@
 // static_assert compat
 #if defined __cplusplus
     #if __cplusplus < 201103L
-        #error "compiler is not supporting C++11 - perhaps not passed std?"
+        #if defined _MSC_VER
+            #if _MSC_VER >= 1914
+                #error "compiler is not advertising C++11 - perhaps not passed /Zc:__cplusplus?"
+            #endif
+            // do nothing for earlier versions - unsolvable, __cplusplus is always 199711L
+        #else
+            #error "compiler is not supporting C++11 - perhaps not passed std?"
+        #endif
     #endif
 #elif __STDC_VERSION__ < 201112L
     #if defined _MSC_VER && _MSC_VER <= 1900