configure: Generate .pc file with variable-prefixed paths

Makefile.in

@@ -31,6 +31,7 @@ distclean:	clean
 	rm -f \
 		Makefile aucat/Makefile midicat/Makefile sndiod/Makefile \
 		libsndio/Makefile \
+		libsndio/sndio.pc \
 		sndioctl/Makefile \
 		examples/Makefile \
 		contrib/init.d.sndiod \

configure

@@ -266,7 +266,7 @@ fi
 
 
 for f in Makefile aucat/Makefile midicat/Makefile sndiod/Makefile \
-libsndio/Makefile libsndio/sndio.pc \
+libsndio/Makefile \
 sndioctl/Makefile \
 examples/Makefile \
 contrib/init.d.sndiod \
@@ -293,6 +293,25 @@ do
 	< $f.in > $f
 done
 
+#
+# Generate sndio.pc. Substitute path prefixes with ${prefix} or
+# ${exec_prefix} variable names, so that they can be overriden by the
+# user
+#
+cat <<EOF >libsndio/sndio.pc
+prefix=${prefix}
+exec_prefix=`echo $exec_prefix | sed -e "s:^${prefix}:\\${prefix}:"`
+libdir=`echo $libdir | sed -e "s:^${exec_prefix}:\\${exec_prefix}:"`
+includedir=`echo $includedir | sed -e "s:^${prefix}:\\${prefix}:"`
+
+Name: sndio
+Description: sndio library
+Version: 1.7.0
+Requires:
+Libs: -L\${libdir} -lsndio
+Cflags: -I\${includedir}
+EOF
+
 chmod +x contrib/init.d.sndiod
 
 cat <<EOF

libsndio/sndio.pc.in

@@ -1,6 +0,0 @@
-Name: sndio
-Description: sndio library
-Version: @version@
-Requires: 
-Libs: -L@libdir@ -lsndio
-Cflags: -I@includedir@