syntax: support `elif` clauses for alternative `if` syntax

In the alternative `if` syntax mode, support a specific `elif` keyword instead
of requiring an `else` branch followed by a disjunct `if` statement.

The advantage is that templates do not require error-prone redundant `endif`
keywords in else-if ladders.

After this change, the following example:

    {% if (...): %}
    One condition
    {% else if (...): %}
    Another condition
    {% else if (...): %}
    A third condition
    {% else %}
    Final condition
    {% endif; endif; endif %}

... can be simplified into:

    {% if (...): %}
    One condition
    {% elif (...): %}
    Another condition
    {% elif (...): %}
    A third condition
    {% else %}
    Final condition
    {% endif %}

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/lexer.h b/lexer.h
index f40c820..46cb9d5 100644
--- a/lexer.h
+++ b/lexer.h
@@ -19,7 +19,7 @@
 
 #include "ast.h"
 
-#define __T_MAX 79
+#define __T_MAX 80
 #define T_EXCEPTION	(__T_MAX + 0)
 #define T_CFUNC		(__T_MAX + 1)
 #define T_RESSOURCE	(__T_MAX + 2)