From 96f91d7a537bc184bba36340548ad00279552640 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Fri, 18 Dec 2020 15:48:00 +1100
Subject: [PATCH 1/2] lib/dns/gen should be built with CC_FOR_BUILD

---
 configure.ac          |  5 +++
 lib/dns/Makefile.am   |  8 ++---
 m4/ax_cc_for_build.m4 | 77 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+), 6 deletions(-)
 create mode 100644 m4/ax_cc_for_build.m4

diff --git a/configure.ac b/configure.ac
index c90014b7e7..25758d06cd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -91,6 +91,11 @@ AC_CANONICAL_HOST
 AC_PROG_CC_C99
 AC_PROG_CPP_WERROR
 
+#
+# Find build compiler when cross compiling
+#
+AX_CC_FOR_BUILD
+
 #
 # Find the machine's endian flavor.
 #
diff --git a/lib/dns/Makefile.am b/lib/dns/Makefile.am
index e830aed295..1800fdcb1a 100644
--- a/lib/dns/Makefile.am
+++ b/lib/dns/Makefile.am
@@ -18,12 +18,8 @@ BUILT_SOURCES =				\
 CLEANFILES =				\
 	$(nodist_libdns_la_SOURCES)
 
-noinst_PROGRAMS = gen
-
-gen_SOURCES = gen.c gen-unix.h
-
-gen_CPPFLAGS =			\
-	$(AM_CPPFLAGS)
+gen$(BUILD_EXEEXT): gen.c gen-unix.h
+	$(CC_FOR_BUILD) -g -I. $(GEN_NEED_OPTARG) $(srcdir)/gen.c -o $@
 
 EXTRA_DIST =		\
 	api		\
diff --git a/m4/ax_cc_for_build.m4 b/m4/ax_cc_for_build.m4
new file mode 100644
index 0000000000..c62ffadbc0
--- /dev/null
+++ b/m4/ax_cc_for_build.m4
@@ -0,0 +1,77 @@
+# ===========================================================================
+#     https://www.gnu.org/software/autoconf-archive/ax_cc_for_build.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CC_FOR_BUILD
+#
+# DESCRIPTION
+#
+#   Find a build-time compiler. Sets CC_FOR_BUILD and EXEEXT_FOR_BUILD.
+#
+# LICENSE
+#
+#   Copyright (c) 2010 Reuben Thomas <rrt@sc3d.org>
+#   Copyright (c) 1999 Richard Henderson <rth@redhat.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 3
+
+dnl Get a default for CC_FOR_BUILD to put into Makefile.
+AC_DEFUN([AX_CC_FOR_BUILD],
+[# Put a plausible default for CC_FOR_BUILD in Makefile.
+if test -z "$CC_FOR_BUILD"; then
+  if test "x$cross_compiling" = "xno"; then
+    CC_FOR_BUILD='$(CC)'
+  else
+    CC_FOR_BUILD=gcc
+  fi
+fi
+AC_SUBST(CC_FOR_BUILD)
+# Also set EXEEXT_FOR_BUILD.
+if test "x$cross_compiling" = "xno"; then
+  EXEEXT_FOR_BUILD='$(EXEEXT)'
+else
+  AC_CACHE_CHECK([for build system executable suffix], bfd_cv_build_exeext,
+    [rm -f conftest*
+     echo 'int main () { return 0; }' > conftest.c
+     bfd_cv_build_exeext=
+     ${CC_FOR_BUILD} -o conftest conftest.c 1>&5 2>&5
+     for file in conftest.*; do
+       case $file in
+       *.c | *.o | *.obj | *.ilk | *.pdb) ;;
+       *) bfd_cv_build_exeext=`echo $file | sed -e s/conftest//` ;;
+       esac
+     done
+     rm -f conftest*
+     test x"${bfd_cv_build_exeext}" = x && bfd_cv_build_exeext=no])
+  EXEEXT_FOR_BUILD=""
+  test x"${bfd_cv_build_exeext}" != xno && EXEEXT_FOR_BUILD=${bfd_cv_build_exeext}
+fi
+AC_SUBST(EXEEXT_FOR_BUILD)])dnl

From 33c907b1c6bd847628927639d4b6d000e335fbb0 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Fri, 18 Dec 2020 16:37:26 +1100
Subject: [PATCH 2/2] don't enable maintainer mode when cross compiling

---
 configure.ac | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 25758d06cd..f95fd2583a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -65,8 +65,11 @@ AC_CONFIG_MACRO_DIR([m4])
 
 #
 # Enable maintainer mode by default only when building from git repository
+# and not cross compling
 #
-AM_MAINTAINER_MODE([m4_ifset([bind_SRCID],[enable],[disable])])
+AS_IF([test "$cross_compiling" = no],
+      [AM_MAINTAINER_MODE(m4_ifset([bind_SRCID],[enable],[disable]))],
+      [AM_MAINTAINER_MODE([disable])])
 
 # Set the library versions
 # https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html