genkeymap: replace hardcoded path with sysconf(sub)dir

genkeymap/Makefile.am

@@ -3,6 +3,7 @@ EXTRA_DIST = \
   readme.txt
 
 AM_CPPFLAGS = \
+  -DXRDP_CFG_PATH=\"${sysconfdir}/${sysconfsubdir}\" \
   -I$(top_srcdir)/common
 
 AM_CFLAGS = $(X_CFLAGS)

genkeymap/genkeymap.c

@@ -93,7 +93,7 @@ usage(const char *programname, int status)
     fprintf(stderr, "Usage: %s [ -k keycode_set] [-c comment] [-c comment...]"
             " out_filename\n", programname);
     fprintf(stderr, "Example: %s -r evdev -c \"en-US pc104 keyboard\" "
-            " /etc/xrdp/km-00000409.toml\n", programname);
+            XRDP_CFG_PATH "/km-00000409.toml\n", programname);
     exit(status);
 }