[master] 34a2c5049 build: Introduce a new contrib/ directory

[Dridi Boukelmoune]

commit 34a2c5049bc731f7dd97d62023494e9f23144141
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Mon Jul 11 11:20:11 2022 +0200

    build: Introduce a new contrib/ directory

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8b20b9016..7dc228ff0 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -16,6 +16,7 @@ parameters:
   configure_args:
     type: string
     default: |
+        --with-contrib \
         --with-unwind \
         --enable-developer-warnings \
         --enable-debugging-symbols \
diff --git a/Makefile.am b/Makefile.am
index 3e84a6cf6..d33f79a70 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -2,6 +2,10 @@ ACLOCAL_AMFLAGS = -I m4 -I .
 
 SUBDIRS = include lib bin vmod etc doc man
 
+if WITH_CONTRIB
+SUBDIRS += contrib
+endif
+
 TESTS = tools/magic_check.sh
 
 pkgconfigdir = $(libdir)/pkgconfig
@@ -35,6 +39,7 @@ AM_DISTCHECK_CONFIGURE_FLAGS = \
     --enable-developer-warnings \
     --enable-debugging-symbols \
     --enable-dependency-tracking \
+    --with-contrib \
     CFLAGS="$(EXTCFLAGS)"
 
 if WITH_UNWIND
diff --git a/autogen.des b/autogen.des
index 294053b87..d256a9bcb 100755
--- a/autogen.des
+++ b/autogen.des
@@ -35,4 +35,5 @@ $SRCDIR/configure \
     --enable-debugging-symbols \
     --enable-dependency-tracking \
     --with-persistent-storage \
+    --with-contrib \
     "$@"
diff --git a/configure.ac b/configure.ac
index ca2bf0b01..57f444a92 100644
--- a/configure.ac
+++ b/configure.ac
@@ -924,4 +924,18 @@ AC_CONFIG_FILES([
     varnishapi-uninstalled.pc
     vmod/Makefile
 ])
+
+AC_ARG_WITH([contrib],
+	[AS_HELP_STRING([--with-contrib],
+		[Build Varnish with external contributions.])])
+
+AM_CONDITIONAL([WITH_CONTRIB], [test "$with_contrib" = yes])
+
+AM_COND_IF([WITH_CONTRIB], [
+	AC_DEFINE([WITH_CONTRIB], [1],
+		[Define to 1 when Varnish is built with contributions.])
+
+	AC_CONFIG_FILES([contrib/Makefile])
+])
+
 AC_OUTPUT
diff --git a/contrib/Makefile.am b/contrib/Makefile.am
new file mode 100644
index 000000000..2c2a87cbf
--- /dev/null
+++ b/contrib/Makefile.am
@@ -0,0 +1,3 @@
+#
+
+