[PATCH] C99 compatibility fix

[Florian Weimer]

I researched this quite a bit, and this approach seems to be the least
bad option.

Future compilers are likely to require functions to be declared before
they can be called.  The flex lexer generator can be taught to create a
header file with the required declarations.  However, automake conspires
against us to use it during the build.  So I extracted the relevant
declarations by hand and put it into a non-generated header file.  At
least the declarations are checked against the definitions in
rec-sex-lex.c, so maybe it's not too bad after all.

Related to:

  <https://fedoraproject.org/wiki/Changes/PortingToModernC>
  <https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

diff --git a/.gitignore b/.gitignore
index e2d1aac..18ed187 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,7 +41,6 @@ libtool
 /src/config.h.in
 /src/stamp-h1
 /src/rec-sex-lex.c
-/src/rec-sex-lex.h
 /src/rec-sex-tab.c
 /src/rec-sex-tab.h
 /torture/runtests
diff --git a/src/rec-sex-lex.h b/src/rec-sex-lex.h
new file mode 100644
index 0000000..4bfc1dc
--- /dev/null
+++ b/src/rec-sex-lex.h
@@ -0,0 +1,7 @@
+/* Declarations exported from the generated lexer. */
+
+int sexlex_init (void **);
+void sexset_extra (void *, void *);
+int sexlex_destroy (void *);
+union YYSTYPE;
+int sexlex (union YYSTYPE *, void *);
diff --git a/src/rec-sex-lex.l b/src/rec-sex-lex.l
index 1e537bf..2d4a891 100644
--- a/src/rec-sex-lex.l
+++ b/src/rec-sex-lex.l
@@ -26,12 +26,12 @@
 %option bison-bridge
 %option extra-type="void *"
 
-%option header-file="rec-sex-lex.h"
 %option nounput
 %option noinput
 %top {
    /* This code goes at the "top" of the generated file.  */
    #include <config.h>
+   #include "rec-sex-lex.h"
 }
 
 %{
diff --git a/src/rec-sex-parser.c b/src/rec-sex-parser.c
index e5bcd33..4eb188a 100644
--- a/src/rec-sex-parser.c
+++ b/src/rec-sex-parser.c
@@ -25,7 +25,7 @@
 
 #include <rec-sex-parser.h>
 #include "rec-sex-tab.h"
-/*#include "rec-sex-lex.h" */
+#include "rec-sex-lex.h"
 
 struct rec_sex_parser_s
 {
diff --git a/src/rec-sex-tab.y b/src/rec-sex-tab.y
index 6c31edd..f011bc4 100644
--- a/src/rec-sex-tab.y
+++ b/src/rec-sex-tab.y
@@ -33,7 +33,7 @@
   #include <rec-sex-ast.h>
   #include <rec-sex-parser.h>
   #include "rec-sex-tab.h"
-  /*  #include "rec-sex-lex.h" */
+  #include "rec-sex-lex.h"
 
   void sexerror (rec_sex_parser_t context, const char *err)
   {

Thanks,
Florian