Add tests for a51d618a fix of RT #122283

Add a new re debug mode for outputing stuff useful for testing.

In this case we count the number of times that we go through
study_chunk. With a51d618a we should do 5 times (or less) when
we traverse the test pattern. Without a51d618a we recurse 11
times. In the case of RT #122283 we would do gazilions of
recursions, so many I never let it run to finish.

    /
        (?(DEFINE)(?<foo>foo))
        (?(DEFINE)(?<bar>(?&foo)bar))
        (?(DEFINE)(?<baz>(?&bar)baz))
        (?(DEFINE)(?<bop>(?&baz)bop))
    /x

I say "or less" because you could argue that since these defines are
never called, we should not actually recurse at all, and should maybe
just compile this as a simple empty pattern.

1 files changed, 3 insertions, 0 deletions

diff --git a/regcomp.h b/regcomp.h
index d4d3a29545..1d41d6e77f 100644
--- a/regcomp.h
+++ b/regcomp.h
@@ -856,6 +856,7 @@ re.pm, especially to the documentation.
 #define RE_DEBUG_COMPILE_TRIE      0x000004
 #define RE_DEBUG_COMPILE_DUMP      0x000008
 #define RE_DEBUG_COMPILE_FLAGS     0x000010
+#define RE_DEBUG_COMPILE_TEST      0x000020
 
 /* Execute */
 #define RE_DEBUG_EXECUTE_MASK      0x00FF00
@@ -891,6 +892,8 @@ re.pm, especially to the documentation.
     if (re_debug_flags & RE_DEBUG_COMPILE_TRIE) x )
 #define DEBUG_FLAGS_r(x) DEBUG_r( \
     if (re_debug_flags & RE_DEBUG_COMPILE_FLAGS) x )
+#define DEBUG_TEST_r(x) DEBUG_r( \
+    if (re_debug_flags & RE_DEBUG_COMPILE_TEST) x )
 /* Execute */
 #define DEBUG_EXECUTE_r(x) DEBUG_r( \
     if (re_debug_flags & RE_DEBUG_EXECUTE_MASK) x  )