Allow to change config file (sub)directory

This allows the `xrdp` part of the path `/etc/xrdp` where config files
are placed to be customizable. This change is useful when trying the
stable version and the devel version alternately.

keygen/Makefile.am

@@ -1,7 +1,7 @@
 EXTRA_DIST = openssl.conf
 
 AM_CPPFLAGS = \
-  -DXRDP_CFG_PATH=\"${sysconfdir}/xrdp\" \
+  -DXRDP_CFG_PATH=\"${sysconfdir}/${sysconfsubdir}\" \
   -DXRDP_SBIN_PATH=\"${sbindir}\" \
   -DXRDP_SHARE_PATH=\"${datadir}/xrdp\" \
   -DXRDP_PID_PATH=\"${localstatedir}/run\" \
@@ -15,7 +15,7 @@ xrdp_keygen_SOURCES = keygen.c
 xrdp_keygen_LDADD = \
   $(top_builddir)/common/libcommon.la
 
-xrdpsysconfdir = $(sysconfdir)/xrdp
+xrdpsysconfdir = $(sysconfdir)/$(sysconfsubdir)
 
 install-data-hook:
 	umask 077 && \