diff --git a/klib/src/platform/windows/posix.def b/klib/src/platform/windows/posix.def
index f6a44bcbe64..ada704b5bb7 100644
--- a/klib/src/platform/windows/posix.def
+++ b/klib/src/platform/windows/posix.def
@@ -1,5 +1,5 @@
 package = platform.posix
-headers = stdio.h Windef.h Winsock2.h Ws2tcpip.h Ws2def.h io.h
+headers = stdio.h Windef.h Winsock2.h Ws2tcpip.h Ws2def.h io.h math.h
 compilerOpts = -DUNICODE -Wno-incompatible-pointer-types -Wno-deprecated-declarations
 linkerOpts = -lWs2_32
 
@@ -28,4 +28,4 @@ static void posix_FD_SET(int bit, fd_set *set) {
 
 static int posix_FD_ISSET(int bit, fd_set *set) {
     return FD_ISSET(bit, set);
-}
\ No newline at end of file
+}