component/postfix: build with slapos libnsl

On debian 11, linking against libnsl link against several system
libraries and the check software check fail.

component/postfix/buildout.cfg

@@ -8,6 +8,7 @@ extends =
   ../patch/buildout.cfg
   ../pcre/buildout.cfg
   ../cyrus-sasl/buildout.cfg
+  ../libnsl/buildout.cfg
   ../m4/buildout.cfg
 
 [postfix]
@@ -20,7 +21,9 @@ patch-options = -p1
 patches =
   ${:_profile_base_location_}/noroot.patch#05fc6333e05576ea8e5a49f27a6ef951
 configure-command = make
-configure-options = makefiles CCARGS='-DUSE_SASL_AUTH -DUSE_CYRUS_SASL -DUSE_TLS -DHAS_PCRE -DHAS_DB -I${libdb:location}/include -I${pcre:location}/include -I${openssl:location}/include -I${cyrus-sasl:location}/include/sasl' AUXLIBS='-L${openssl:location}/lib -L${pcre:location}/lib -L${libdb:location}/lib -L${cyrus-sasl:location}/lib -lssl -lpcre -ldb -lcrypto -lsasl2 -Wl,-rpath=${openssl:location}/lib -Wl,-rpath=${pcre:location}/lib -Wl,-rpath=${libdb:location}/lib -Wl,-rpath=${cyrus-sasl:location}/lib'
+configure-options = makefiles CCARGS=${:configure-options-CCARGS} AUXLIBS=${:configure-options-AUXLIBS}
+configure-options-CCARGS = '-DUSE_SASL_AUTH -DUSE_CYRUS_SASL -DUSE_TLS -DHAS_PCRE -DHAS_DB -I${libdb:location}/include -I${pcre:location}/include -I${openssl:location}/include -I${cyrus-sasl:location}/include/sasl -I${libnsl:location}/include'
+configure-options-AUXLIBS = '-L${openssl:location}/lib -L${pcre:location}/lib -L${libdb:location}/lib -L${cyrus-sasl:location}/lib -L${libtirpc:location}/lib -L${libnsl:location}/lib -lssl -lpcre -ldb -lcrypto -lsasl2 -Wl,-rpath=${openssl:location}/lib -Wl,-rpath=${pcre:location}/lib -Wl,-rpath=${libdb:location}/lib -Wl,-rpath=${cyrus-sasl:location}/lib  -Wl,-rpath=${libnsl:location}/lib' 
 make-targets = non-interactive-package install_root=${:location}
 environment =
   PATH=${patch:location}/bin:${m4:location}/bin:%(PATH)s