diff --git a/scripts/genie.lua b/scripts/genie.lua
index 94ddbffe257..827d27709c0 100644
--- a/scripts/genie.lua
+++ b/scripts/genie.lua
@@ -910,6 +910,7 @@ end
 configuration { "mingw-clang" }
 	buildoptions {
 		"-Xclang -flto-visibility-public-std", -- workround for __imp___ link errors
+		"-Wno-nonportable-include-path", -- workround for clang 9.0.0 case sensitivity bug when including GL/glext.h
 	}
 configuration {  }
 
diff --git a/scripts/src/3rdparty.lua b/scripts/src/3rdparty.lua
index 196c5c5688d..c80075bf9f1 100644
--- a/scripts/src/3rdparty.lua
+++ b/scripts/src/3rdparty.lua
@@ -1206,7 +1206,7 @@ project "bimg"
 
 	configuration { }
 
-	if _OPTIONS["targetos"]=="macosx" or  _OPTIONS["targetos"]=="linux" then
+	if _OPTIONS["targetos"]=="macosx" or _OPTIONS["targetos"]=="linux" or _OPTIONS["targetos"]=="windows" then
 		if _OPTIONS["gcc"]~=nil and string.find(_OPTIONS["gcc"], "clang") then
 			buildoptions_cpp {
 				"-Wno-unused-const-variable",