component/proftpd: build mod_auth_web with rpath

This build command never used the LDFLAGS that we set, so instead
rewrite this to inject path as a -R option that will be passed to
libtool.

component/proftpd/buildout.cfg

@@ -32,12 +32,10 @@ configure-options =
   --with-modules=mod_sftp:mod_ban
   --prefix=${buildout:parts-directory}/${:_buildout_section_name_}
 environment = 
-  CPPFLAGS=${:cppflags}
-  LDFLAGS=${:ldflags}
+  CPPFLAGS=-I${zlib:location}/include -I${openssl:location}/include
+  LDFLAGS=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${openssl:location}/lib -Wl,-rpath=${openssl:location}/lib
   install_user=${proftpd-environment:USER}
   install_group=${proftpd-grp:GROUP}
-cppflags=-I${zlib:location}/include -I${openssl:location}/include
-ldflags=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${openssl:location}/lib -Wl,-rpath=${openssl:location}/lib
 patch-binary = ${patch:location}/bin/patch
 patch-options = -p1
 patches =
@@ -56,14 +54,14 @@ git-executable = ${git:location}/bin/git
 [proftpd-mod_auth_web]
 recipe = plone.recipe.command
 stop-on-error = true
+# prxs does not support setting rpath, but we can "inject" -R that will be passed to libtool
 command =
   LIBTOOL=${libtool:location}/bin/libtool \
-  LDFLAGS="-Wl,-rpath=${curl:location}/lib ${proftpd:ldflags}" \
-  ${proftpd-output:prxs} -c -i \
-  -I ${curl:location}/include ${proftpd:cppflags} \
-  -L ${curl:location}/lib/ \
+  ${proftpd-output:prxs} -c -i -d \
+  -I ${curl:location}/include \
+  -L '${curl:location}/lib/ -R ${openssl:location}/lib -R ${zlib:location}/lib' \
   -l curl \
-  -d ${proftpd-mod_auth_web-repository:location}/mod_auth_web.c
+  ${proftpd-mod_auth_web-repository:location}/mod_auth_web.c
 location=${proftpd:location}/libexec/mod_auth_web.so