Look for soundcard.h in /usr/include/sys, /usr/include/linux, and /usr/include

src/xpdev/GNUmakefile

@@ -7,6 +7,7 @@ endif
 MTOBJS	+=	$(MTOBJODIR)$(DIRSEP)xpevent$(OFILE)
 
 MT_CFLAGS += -DLINK_LIST_THREADSAFE
+CFLAGS	+=	-DSOUNDCARD_H_IN=$(shell if [ -e /usr/include/sys/soundcard.h ] ; then echo SYS ; elif [ -e /usr/include/soundcard.h ] ; then echo INCLUDE ; elif [ -e /usr/include/linux/soundcard.h ] ; then echo LINUX ; else echo NONE ; fi)
 
 # Executable Build Rule
 $(WRAPTEST): $(OBJODIR)/wraptest.o $(DEPS)

src/xpdev/xpbeep.c

@@ -6,8 +6,15 @@
 	#include <mmsystem.h>
 #elif defined(__unix__)
 	#include <fcntl.h>
-	#include <soundcard.h>
-	#include <sys/soundcard.h>
+	#if SOUNDCARD_H_IN==SYS
+		#include <sys/soundcard.h>
+	#elif SOUNDCARD_H_IN==INCLUDE
+		#include <soundcard.h>
+	#elif SOUNDCARD_H_IN==LINUX
+		#include <linux/soundcard.h>
+	#else
+		#warning Cannot find soundcard.h
+	#endif
 	/* KIOCSOUND */
 	#if defined(__FreeBSD__)
 		#include <sys/kbio.h>