Add configure test for slot support in libgerbv.

Since slot support in gerbv is quite new, ensure that configure
detects old versions which do not support this feature and fail
early.

diff --git a/configure.ac b/configure.ac
index d5024213caf01f8bfb4959f53082ede33cda48b2..f5c7c70dc80a5437a17f90972cf56eb749498de3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-dnl Copyright © 2018 Nick Bowler
+dnl Copyright © 2018-2019 Nick Bowler

 dnl
 dnl License WTFPL2: Do What The Fuck You Want To Public License, version 2.
 dnl This is free software: you are free to do what the fuck you want to.
 dnl
 dnl License WTFPL2: Do What The Fuck You Want To Public License, version 2.
 dnl This is free software: you are free to do what the fuck you want to.


@@ -17,6 +17,8 @@ gl_EARLY
 LT_INIT
 gl_INIT
 
 LT_INIT
 gl_INIT
 

+AC_CACHE_SAVE
+

 m4_include([lib/gnulib.mk])
 
 dnl We provide our own makefile rules for gettext.  Disable tracing of
 m4_include([lib/gnulib.mk])
 
 dnl We provide our own makefile rules for gettext.  Disable tracing of


@@ -26,8 +28,28 @@ m4_traceoff([AM_GNU_GETTEXT])
 AM_GNU_GETTEXT([external])
 DX_LINGUAS
 
 AM_GNU_GETTEXT([external])
 DX_LINGUAS
 

-DX_LIB_LIBGERBV

 DX_LIB_CNEARTREE
 DX_LIB_CNEARTREE

+DX_LIB_LIBGERBV
+
+AS_IF([test x"$dx_cv_libgerbv_lib_found" = x"yes"],
+[AC_CACHE_CHECK([if libgerbv supports G85 slots], [dx_cv_gerbv_supports_g85],
+[save_CFLAGS=$CFLAGS
+CFLAGS="$CFLAGS $LIBGERBV_CFLAGS"
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+[#include <gerbv.h>
+#include <stddef.h>
+], [static int g85_supported@<:@
+  offsetof(gerbv_drill_stats_t, G85) >= 0 ? 1 : -1
+@:>@;])], [dx_cv_gerbv_supports_g85=yes], [dx_cv_gerbv_supports_g85=no])
+CFLAGS=$save_CFLAGS])])
+
+AS_IF([test x"$dx_cv_gerbv_supports_g85" != x"yes"],
+[AC_MSG_FAILURE([Your installation of libgerbv appears not to
+support slots.  An updated version of libgerbv is likely required.
+The latest version may be found at <http://gerbv.geda-project.org/>.
+m4_newline([DX_LIB_USERFLAG_BLURB([libgerbv])])
+m4_newline([DX_LIB_PKGCONFIG_BLURB([libgerbv])])
+])])

 
 AC_CONFIG_TESTDIR([.])
 DX_PROG_AUTOTEST
 
 AC_CONFIG_TESTDIR([.])
 DX_PROG_AUTOTEST