dfa.c badly broken when dropped into gawk

[Arnold Robbins]

Hi.

The current dfa.[ch] are badly broken when dropped into gawk.  To
reproduce:

1. Checkout the gawk repo
2. Copy gnulib/lib/dfa.[ch] into gawk/support/.
3. Apply the minimal patch below

Then the usual `./bootstrap.sh && ./configure && make -j && make check'.
You'll see lots of the tests blowing up spectacularly.

Please repair things.

Thanks,

Arnold
----------------------------------------
diff --git a/lib/dfa.c b/lib/dfa.c
index 8c88c9d..818f58f 100644
--- a/lib/dfa.c
+++ b/lib/dfa.c
@@ -890,6 +890,23 @@ char_context (struct dfa const *dfa, unsigned char c)
   return CTX_NONE;
 }
 
+/* Copy the syntax settings from one dfa instance to another.
+   Saves considerable computation time if compiling many regular expressions
+   based on the same setting.  */
+void
+dfacopysyntax (struct dfa *to, const struct dfa *from)
+{
+  to->dfaexec = from->dfaexec;
+  to->simple_locale = from->simple_locale;
+  to->localeinfo = from->localeinfo;
+
+  to->fast = from->fast;
+
+  to->canychar = from->canychar;
+  to->lex.cur_mb_len = from->lex.cur_mb_len;
+  to->syntax = from->syntax;
+}
+
 /* Set a bit in the charclass for the given wchar_t.  Do nothing if WC
    is represented by a multi-byte sequence.  Even for MB_CUR_MAX == 1,
    this may happen when folding case in weird Turkish locales where
diff --git a/lib/dfa.h b/lib/dfa.h
index 96c3bf1..c6dc786 100644
--- a/lib/dfa.h
+++ b/lib/dfa.h
@@ -42,7 +42,7 @@ struct dfa;
 /* Allocate a struct dfa.  The struct dfa is completely opaque.
    The returned pointer should be passed directly to free() after
    calling dfafree() on it. */
-extern struct dfa *dfaalloc (void) _GL_ATTRIBUTE_MALLOC;
+extern struct dfa *dfaalloc (void) /* _GL_ATTRIBUTE_MALLOC */ ;
 
 /* DFA options that can be ORed together, for dfasyntax's 4th arg.  */
 enum
@@ -105,6 +105,11 @@ extern struct dfa *dfasuperset (struct dfa const *d) 
_GL_ATTRIBUTE_PURE;
 /* The DFA is likely to be fast.  */
 extern bool dfaisfast (struct dfa const *) _GL_ATTRIBUTE_PURE;
 
+/* Copy the syntax settings from one dfa instance to another.
+   Saves considerable computation time if compiling many regular expressions
+   based on the same setting.  */
+extern void dfacopysyntax (struct dfa *to, const struct dfa *from);
+
 /* Free the storage held by the components of a struct dfa. */
 extern void dfafree (struct dfa *);