diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
index ca979d95e13c..f8e34ad6e6fa 100644
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -54,6 +54,7 @@ endif ()
 
 # CodeGen options.
 check_c_compiler_flag(-ffreestanding         COMPILER_RT_HAS_FFREESTANDING_FLAG)
+check_c_compiler_flag(-std=c11               COMPILER_RT_HAS_STD_C11_FLAG)
 check_cxx_compiler_flag(-fPIC                COMPILER_RT_HAS_FPIC_FLAG)
 check_cxx_compiler_flag(-fPIE                COMPILER_RT_HAS_FPIE_FLAG)
 check_cxx_compiler_flag(-fno-builtin         COMPILER_RT_HAS_FNO_BUILTIN_FLAG)
diff --git a/compiler-rt/lib/crt/CMakeLists.txt b/compiler-rt/lib/crt/CMakeLists.txt
index a82ae75c56a3..790387bc71a6 100644
--- a/compiler-rt/lib/crt/CMakeLists.txt
+++ b/compiler-rt/lib/crt/CMakeLists.txt
@@ -71,6 +71,7 @@ endfunction()
 check_cxx_section_exists(".init_array" COMPILER_RT_HAS_INITFINI_ARRAY
   SOURCE "__attribute__((constructor)) void f() {}\nint main() { return 0; }\n")
 
+append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 CRT_CFLAGS)
 append_list_if(COMPILER_RT_HAS_INITFINI_ARRAY -DCRT_HAS_INITFINI_ARRAY CRT_CFLAGS)
 append_list_if(COMPILER_RT_HAS_FPIC_FLAG -fPIC CRT_CFLAGS)
 append_list_if(COMPILER_RT_HAS_WNO_PEDANTIC -Wno-pedantic CRT_CFLAGS)