build with C11 on MSVC where it's supported

Author: QuietMisdreavus

api_test/CMakeLists.txt

@@ -29,3 +29,8 @@ if(MSVC)
 elseif(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_C_COMPILER_ID}" STREQUAL "Clang")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -std=c99 -pedantic")
 endif()
+
+# On MSVC 15.0 and newer, compile with C11 standard
+if (MSVC AND MSVC_VERSION GREATER_EQUAL 1910)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /std:c11")
+endif()

extensions/CMakeLists.txt

@@ -125,6 +125,11 @@ if(MSVC AND MSVC_VERSION LESS 1800)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /TP")
 endif()
 
+# On MSVC 15.0 and newer, compile with C11 standard
+if (MSVC AND MSVC_VERSION GREATER_EQUAL 1910)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /std:c11")
+endif()
+
 if(CMAKE_BUILD_TYPE STREQUAL "Ubsan")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=undefined")
 endif()

src/CMakeLists.txt

@@ -204,6 +204,11 @@ if(MSVC AND MSVC_VERSION LESS 1800)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /TP")
 endif()
 
+# On MSVC 15.0 and newer, compile with C11 standard
+if (MSVC AND MSVC_VERSION GREATER_EQUAL 1910)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /std:c11")
+endif()
+
 if(CMAKE_BUILD_TYPE STREQUAL "Ubsan")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=undefined")
 endif()