core: main.c - show examples for use of -A for defines with values

src/main.c

@@ -157,7 +157,8 @@ Options:\n\
                   disable with no or off\n\
     --alias=val  Add an alias, the value has to be '[proto:]hostname[:port]'\n\
                   (like for 'alias' global parameter)\n\
-    -A define    Add config pre-processor define (e.g., -A WITH_AUTH)\n\
+    -A define    Add config pre-processor define (e.g., -A WITH_AUTH,\n\
+                  -A 'FLT_ACC=1', -A 'DEFVAL=\"str-val\"')\n\
     -b nr        Maximum receive buffer size which will not be exceeded by\n\
                   auto-probing procedure even if  OS allows\n\
     -c           Check configuration file for syntax errors\n\