--- openal-soft-1.18.2/CMakeLists.txt.orig	2017-09-24 15:41:50.000000000 +0200
+++ openal-soft-1.18.2/CMakeLists.txt	2017-10-31 11:31:20.368269200 +0100
@@ -574,7 +574,10 @@
 
 
 # Check if we have Windows headers
+IF(WIN32 AND NOT CYGWIN)
 CHECK_INCLUDE_FILE(windows.h HAVE_WINDOWS_H -D_WIN32_WINNT=0x0502)
+ENDIF(WIN32 AND NOT CYGWIN)
+
 IF(NOT HAVE_WINDOWS_H)
     CHECK_SYMBOL_EXISTS(gettimeofday sys/time.h HAVE_GETTIMEOFDAY)
     IF(NOT HAVE_GETTIMEOFDAY)