Made libisofs ready for building out-of-source. Thanks Ross Burton.

Makefile.am

@@ -1,6 +1,6 @@
 
 # Copyright (c) 2007 Vreixo Formoso
-# Copyright (c) 2009 - 2018 Thomas Schmitt
+# Copyright (c) 2009 - 2019 Thomas Schmitt
 # Provided under the terms of the GNU General Public License version 2 or later.
 
 # ts A90315 : LIBBURNIA_PKGCONFDIR is defined OS specific in acinclude.m4
@@ -11,6 +11,7 @@ libincludedir=$(includedir)/libisofs
 
 lib_LTLIBRARIES = libisofs/libisofs.la
 ACLOCAL_AMFLAGS = -I ./
+AM_CPPFLAGS = -I $(top_builddir)/libisofs
 
 ## ========================================================================= ##
 
@@ -118,7 +119,7 @@ noinst_PROGRAMS = \
 
 # ts A90807
 # Consolidated demo code for having less linker mesages with a make run.
-demo_demo_CPPFLAGS = -Ilibisofs
+demo_demo_CPPFLAGS = -I $(top_srcdir)/libisofs
 demo_demo_LDADD = $(libisofs_libisofs_la_OBJECTS) $(libisofs_libisofs_la_LIBADD)
 demo_demo_SOURCES = demo/demo.c
 

acinclude.m4

@@ -1,5 +1,5 @@
 
-dnl Copyright (c) 2009 - 2018 Thomas Schmitt
+dnl Copyright (c) 2009 - 2019 Thomas Schmitt
 dnl Provided under the terms of the GNU General Public License version 2 or later.
 
 
@@ -149,12 +149,12 @@ dnl It tests whether -Wl,--version-script=... works with the compiler
 AC_DEFUN([LIBISOFS_ASSERT_VERS_LIBS],
 [
     libburnia_save_LDFLAGS="$LDFLAGS"
-    LDFLAGS="$LDFLAGS -Wl,--version-script=libisofs/libisofs.ver"
+    LDFLAGS="$LDFLAGS -Wl,--version-script=$srcdir/libisofs/libisofs.ver"
     AC_TRY_LINK([#include <stdio.h>], [printf("Hello\n");],
                 [vers_libs_test="yes"], [vers_libs_test="no"])
     if test x$vers_libs_test = xyes
     then
-        LIBLDFLAGS="-Wl,--version-script=libisofs/libisofs.ver"
+        LIBLDFLAGS="-Wl,--version-script=$srcdir/libisofs/libisofs.ver"
     fi
     LDFLAGS="$libburnia_save_LDFLAGS"
     AC_SUBST(LIBLDFLAGS)