http://lists.mplayerhq.hu/pipermail/dvdnav-discuss/2012-March/001672.html

use pkg-config for libdvdread by default rather than the ugly xxx-config scripts

https://bugs.gentoo.org/410189

hassle vapier@gentoo.org if this causes issues

--- configure.ac	(revision 1243)
+++ configure.ac	(working copy)
@@ -89,6 +89,7 @@ AC_PROG_CC
 AC_PROG_MAKE_SET
 AC_PROG_INSTALL
 AC_PROG_LN_S
+PKG_PROG_PKG_CONFIG
 
 dnl --------------------------------------------------------------
 dnl Libtool
@@ -185,15 +186,26 @@ AC_ARG_WITH([dvdread-config],
   [AS_HELP_STRING([--with-dvdread-config=PROG],
     [dvdread-config program to use @<:@default=from PATH@:>@])],
   [DVDREAD_CONFIG="$withval"],
-  [dnl User didn't specify program, search PATH
-  AC_PATH_PROG([DVDREAD_CONFIG], [dvdread-config], [no])
-  test "x$DVDREAD_CONFIG" = xno && \
-    AC_MSG_ERROR([dvdread-config required to link with libdvdread])
-  ])
-DVDREAD_CFLAGS=`$DVDREAD_CONFIG --cflags` || \
-  AC_MSG_ERROR([Could not get libdvdread CFLAGS from $DVDREAD_CONFIG])
-DVDREAD_LIBS=`$DVDREAD_CONFIG --libs` || \
-  AC_MSG_ERROR([Could not get libdvdread LIBS from $DVDREAD_CONFIG])
+  [DVDREAD_CONFIG=""])
+
+dnl by default, search pkg-config, and then fall back to dvdread-config
+DVDREAD_PKG_CONFIG="no"
+if test "x$DVDREAD_CONFIG" = "x"; then
+  PKG_CHECK_MODULES([DVDREAD], [dvdread],
+    [DVDREAD_PKG_CONFIG="yes"],
+    [dnl User didn't specify program, search PATH
+      AC_PATH_PROG([DVDREAD_CONFIG], [dvdread-config], [no])
+      test "x$DVDREAD_CONFIG" = xno && \
+      AC_MSG_ERROR([dvdread-config required to link with libdvdread])
+    ])
+fi
+if test "x$DVDREAD_PKG_CONFIG" != "xyes"; then
+  DVDREAD_CFLAGS=`$DVDREAD_CONFIG --cflags` || \
+    AC_MSG_ERROR([Could not get libdvdread CFLAGS from $DVDREAD_CONFIG])
+  DVDREAD_LIBS=`$DVDREAD_CONFIG --libs` || \
+    AC_MSG_ERROR([Could not get libdvdread LIBS from $DVDREAD_CONFIG])
+fi
+
 AC_SUBST([DVDREAD_CFLAGS])
 AC_SUBST([DVDREAD_LIBS])