diff -Naur compiler-rt-11.1.0rc2.src.orig/cmake/config-ix.cmake compiler-rt-11.1.0rc2.src/cmake/config-ix.cmake
--- compiler-rt-11.1.0rc2.src.orig/cmake/config-ix.cmake	2021-02-15 15:16:53.000000000 +0100
+++ compiler-rt-11.1.0rc2.src/cmake/config-ix.cmake	2021-02-15 15:27:03.000000000 +0100
@@ -85,15 +85,15 @@
   check_cxx_compiler_flag("-fvisibility-inlines-hidden" COMPILER_RT_HAS_FVISIBILITY_INLINES_HIDDEN_FLAG)
 endif()
 
-check_cxx_compiler_flag(/GR COMPILER_RT_HAS_GR_FLAG)
-check_cxx_compiler_flag(/GS COMPILER_RT_HAS_GS_FLAG)
-check_cxx_compiler_flag(/MT COMPILER_RT_HAS_MT_FLAG)
-check_cxx_compiler_flag(/Oy COMPILER_RT_HAS_Oy_FLAG)
+#check_cxx_compiler_flag(/GR COMPILER_RT_HAS_GR_FLAG)
+#check_cxx_compiler_flag(/GS COMPILER_RT_HAS_GS_FLAG)
+#check_cxx_compiler_flag(/MT COMPILER_RT_HAS_MT_FLAG)
+#check_cxx_compiler_flag(/Oy COMPILER_RT_HAS_Oy_FLAG)
 
 # Debug info flags.
 check_cxx_compiler_flag(-gline-tables-only COMPILER_RT_HAS_GLINE_TABLES_ONLY_FLAG)
 check_cxx_compiler_flag(-g COMPILER_RT_HAS_G_FLAG)
-check_cxx_compiler_flag(/Zi COMPILER_RT_HAS_Zi_FLAG)
+#check_cxx_compiler_flag(/Zi COMPILER_RT_HAS_Zi_FLAG)
 
 # Warnings.
 check_cxx_compiler_flag(-Wall COMPILER_RT_HAS_WALL_FLAG)
@@ -108,14 +108,14 @@
 check_cxx_compiler_flag("-Werror -Wcovered-switch-default" COMPILER_RT_HAS_WCOVERED_SWITCH_DEFAULT_FLAG)
 check_cxx_compiler_flag(-Wno-pedantic COMPILER_RT_HAS_WNO_PEDANTIC)
 
-check_cxx_compiler_flag(/W4 COMPILER_RT_HAS_W4_FLAG)
-check_cxx_compiler_flag(/WX COMPILER_RT_HAS_WX_FLAG)
-check_cxx_compiler_flag(/wd4146 COMPILER_RT_HAS_WD4146_FLAG)
-check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)
-check_cxx_compiler_flag(/wd4221 COMPILER_RT_HAS_WD4221_FLAG)
-check_cxx_compiler_flag(/wd4391 COMPILER_RT_HAS_WD4391_FLAG)
-check_cxx_compiler_flag(/wd4722 COMPILER_RT_HAS_WD4722_FLAG)
-check_cxx_compiler_flag(/wd4800 COMPILER_RT_HAS_WD4800_FLAG)
+#check_cxx_compiler_flag(/W4 COMPILER_RT_HAS_W4_FLAG)
+#check_cxx_compiler_flag(/WX COMPILER_RT_HAS_WX_FLAG)
+#check_cxx_compiler_flag(/wd4146 COMPILER_RT_HAS_WD4146_FLAG)
+#check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)
+#check_cxx_compiler_flag(/wd4221 COMPILER_RT_HAS_WD4221_FLAG)
+#check_cxx_compiler_flag(/wd4391 COMPILER_RT_HAS_WD4391_FLAG)
+#check_cxx_compiler_flag(/wd4722 COMPILER_RT_HAS_WD4722_FLAG)
+#check_cxx_compiler_flag(/wd4800 COMPILER_RT_HAS_WD4800_FLAG)
 
 # Symbols.
 check_symbol_exists(__func__ "" COMPILER_RT_HAS_FUNC_SYMBOL)