ccproject: fix segfault with empty command

Don't analyze a compile command with an empty (null) "command"

Closes #163

Author: thestr4ng3r

src/projects/ccproject.vala

@@ -62,7 +62,12 @@ class Vls.CcProject : Project {
             if (cc == null)
                 throw new ProjectError.INTROSPECTION (@"JSON node is null. Bailing out!");
 
-            if (cc.command.length > 0 && cc.command[0].contains ("valac"))
+            if (cc.command.length == 0) {
+                warning ("CC#%d has empty command list", i);
+                continue;
+            }
+
+            if (cc.command[0].contains ("valac"))
                 build_targets.add (new Compilation (cc.directory, cc.file ?? @"CC#$i", @"CC#$i", i,
                                                     cc.command[0:1], cc.command[1:cc.command.length],
                                                     new string[]{}, new string[]{}));

src/projects/types.vala

@@ -54,7 +54,9 @@ namespace Vls {
                 val = Value (typeof (string[]));
                 string[] command_array = {};
                 try {
-                    command_array = Util.get_arguments_from_command_str (property_node.get_string ());
+                    string? command_str = property_node.get_string ();
+                    if (command_str != null)
+                        command_array = Util.get_arguments_from_command_str (property_node.get_string ());
                 } catch (RegexError e) {
                     warning ("failed to parse `%s': %s", property_node.get_string (), e.message);
                 }