Found some engine sounds on the net.

Added a test for the OSS sound system to autoconf.
Added a Lib/Audio subdirectory.

Thanks

@@ -95,6 +95,12 @@ Alan Murta <amurta@cs.man.ac.uk>
   Created the Generic Polygon Clipping library
 
 
+Oscar <bigoc@premier.net>
+  Created single engine piston engine sounds as part of an F4U package
+  for FS98.  They are pretty cool and Oscar was happy to contribute
+  them to our little project.
+
+
 Jonathan R Shewchuk <Jonathan_R_Shewchuk@ux4.sp.cs.cmu.edu>
   Author of the Triangle program.  Triangle is used to calculate the
   Delauney triangulation of our irregular terrain.

aclocal.m4

@@ -385,6 +385,19 @@ rm -f conftest*])
 CYGWIN32=
 test "$am_cv_cygwin32" = yes && CYGWIN32=yes])
 
+# Define a conditional.
+
+AC_DEFUN(AM_CONDITIONAL,
+[AC_SUBST($1_TRUE)
+AC_SUBST($1_FALSE)
+if $2; then
+  $1_TRUE=
+  $1_FALSE='#'
+else
+  $1_TRUE='#'
+  $1_FALSE=
+fi])
+
 # Like AC_CONFIG_HEADER, but automatically create stamp file.
 
 AC_DEFUN(AM_CONFIG_HEADER,

configure.in

@@ -23,6 +23,10 @@ AM_MAINTAINER_MODE
 dnl Check to see if this `configure' is being run in the `Cygwin32' environment
 AM_CYGWIN32
 
+dnl Check for Linux style audio support
+AM_CONDITIONAL(HAVE_OSS_AUDIO, \
+	test -r /usr/include/soundcard.h -o -r /usr/include/linux/soundcard.h )
+
 AC_CHECK_HEADER(windows.h)
 
 dnl extra library and include directories