./all: drop into gdb if a crash happened and gdb is available (otherwise keep using catchsegv)

all

@@ -666,12 +666,21 @@ case "$cmd" in
 			fi
 		fi
 
+		binary=$1
+
 		if [ -n "$USE_GDB" ]; then
 			set -- gdb --args "$@"
+		elif which gdb >/dev/null 2>&1; then
+			set -- gdb --batch -x savecore.gdb --args "$@"
 		elif which catchsegv >/dev/null 2>&1; then
 			set -- catchsegv "$@"
 		fi
+		rm -f xonotic.core
 		"$@"
+		if [ -f xonotic.core ]; then
+			echo "The program has CRASHED. Please examine the core dump in the debugger."
+			gdb "$binary" xonotic.core
+		fi
 		;;
 	each|foreach)
 		keep_going=false

savecore.gdb

@@ -0,0 +1,5 @@
+run
+set pagination off
+echo \n\nIf the following commands show errors, that can be ignored:\n
+bt
+generate-core-file xonotic.core