Fix gdb logfile command overwriting the old logfile

on my debian laptop with peda it seems like
the gdb internal log command clears out the logfile before writing to it
that is bad because we lose the previous crash log
and also the manually written header with the commit
hash

So this commit makes sure that no matter the gdb setup it will
only append and never delete old logs

lib/include/gdb_loop.sh

@@ -91,6 +91,10 @@ then
 	err "failed to get commit hash"
 	exit 1
 fi
+
+gdb_tmp_log_header="$p/full_gdb.header.txt.tmp"
+gdb_tmp_log_gdb="$p/full_gdb.gdb.txt.tmp"
+
 read -rd '' GDB_CMD << EOF
 $CFG_ENV_RUNTIME gdb -ex='set confirm off' \
     -ex='set pagination off' \
@@ -100,7 +104,7 @@ $CFG_ENV_RUNTIME gdb -ex='set confirm off' \
     -ex='set logging on' \
     -ex=bt \
     -ex='set logging off' \
-    -ex="set logging file $p/full_gdb.txt" \
+    -ex="set logging file $gdb_tmp_log_gdb" \
     -ex='set logging on' \
     -ex='echo (gdb) bt full\\n' -ex='bt full' \
     -ex='echo (gdb) info registers\\n' -ex='info registers' \
@@ -124,11 +128,17 @@ start_ts=$(date '+%Y-%m-%d %H:%M:%S')
 	echo "gdb ./bin/backup/$(get_commit) $gdb_corefile"
 	echo "objdump -dCS -M intel bin/backup/$(get_commit) > ./lib/tmp/debug.asm && vim ./lib/tmp/debug.asm"
 	echo "python -c 'print(hex(0xbabe + 10))'"
-} >> "$p/full_gdb.txt"
+} >> "$gdb_tmp_log_header"
 echo ""
 eval "$GDB_CMD"
 echo ""
 log "executed: '$GDB_CMD'"
+
+cat "$gdb_tmp_log_header" >> "$p/full_gdb.txt"
+rm "$gdb_tmp_log_header"
+cat "$gdb_tmp_log_gdb" >> "$p/full_gdb.txt"
+rm "$gdb_tmp_log_gdb"
+
 stop_ts=$(date '+%Y-%m-%d %H:%M:%S')
 echo "\\============= server stop  $stop_ts =============/" >> "$p/full_gdb.txt"
 echo "/============= server start $start_ts =============\\" > "$p/raw_gdb.txt"