[gjs/wip/ptomato/autotools: 12/16] build: Improve readline check

[Philip Chimento <pchimento src gnome org>]

commit eafb2f072b2d222fc47daa66da0906f933c06142
Author: Philip Chimento <philip chimento gmail com>
Date:   Mon Sep 26 22:39:33 2016 -0700

    build: Improve readline check
    
    The AC_TRY_CPP macro is deprecated, and Automake provides a better macro
    to use: AC_CHECK_HEADERS. This works despite the possibly extra required
    linker flags because we call it within the scope where we have readline's
    flags added to LIBS.
    
    AC_CHECK_HEADERS defines its own preprocessor symbol with the result, so
    we can use that. The AM_CONDITIONAL symbol was unused anyway, so that can
    be removed.

 configure.ac        |   11 +++--------
 modules/console.cpp |    4 ++--
 2 files changed, 5 insertions(+), 10 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5f9ad85..9b713b5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -140,18 +140,13 @@ done
 if test $gjs_cv_lib_readline = no; then
   AC_MSG_RESULT([none])
   READLINE_LIBS=""
+  ac_cv_header_readline_readline_h=no
 else
   AC_MSG_RESULT([$READLINE_LIBS])
-  AC_DEFINE(HAVE_LIBREADLINE, 1,
-    [Define if you have the readline library (-lreadline).])
+  AC_CHECK_HEADERS([readline/readline.h])
 fi
 
-AC_TRY_CPP([#include <readline/readline.h>],
-have_readline=yes, have_readline=no)
-
-AM_CONDITIONAL([HAVE_READLINE], [test x$have_readline = xyes])
 AC_SUBST([READLINE_LIBS])
-AC_SUBST([HAVE_READLINE])
 
 # End of readline checks: restore LIBS
 LIBS=$LIBS_no_readline
@@ -247,7 +242,7 @@ AC_MSG_RESULT([
 
        cairo:                  ${have_cairo}
        GTK+:                   ${have_gtk}
-       readline:               ${have_readline}
+       readline:               ${ac_cv_header_readline_readline_h}
        dtrace:                 ${ENABLE_DTRACE}
        systemtap:              ${ENABLE_SYSTEMTAP}
        Run tests under:        ${TEST_MSG}
diff --git a/modules/console.cpp b/modules/console.cpp
index 9fc9d8d..a85ed50 100644
--- a/modules/console.cpp
+++ b/modules/console.cpp
@@ -43,7 +43,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#ifdef HAVE_LIBREADLINE
+#ifdef HAVE_READLINE_READLINE_H
 #include <stdio.h>
 #include <readline/readline.h>
 #include <readline/history.h>
@@ -127,7 +127,7 @@ gjs_console_error_reporter(JSContext *cx, const char *message, JSErrorReport *re
     g_free(prefix);
 }
 
-#ifdef HAVE_LIBREADLINE
+#ifdef HAVE_READLINE_READLINE_H
 static JSBool
 gjs_console_readline(JSContext *cx, char **bufp, FILE *file, const char *prompt)
 {