Check for stdbool.h at configuration stage, and include it if available.

Check for lowercase 'bool' type at configuration stage. If not available
provide a suitable replacement with a type definition of 'unsigned char'
in setup_once.h

Move definitions of TRUE and FALSE to setup_once.h

ares_process.c

@@ -54,10 +54,6 @@
 #include "ares_dns.h"
 #include "ares_private.h"
 
-#ifndef TRUE
-/* at least Solaris 7 does not have TRUE at this point */
-#define TRUE 1
-#endif
 
 static int try_again(int errnum);
 static void write_tcp_data(ares_channel channel, fd_set *write_fds,
@@ -532,7 +528,7 @@ static int nonblock(ares_socket_t sockfd,    /* operate on this */
   int flags;
 
   flags = fcntl(sockfd, F_GETFL, 0);
-  if (TRUE == nonblock)
+  if (FALSE != nonblock)
     return fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
   else
     return fcntl(sockfd, F_SETFL, flags & (~O_NONBLOCK));

configure.ac

@@ -308,6 +308,8 @@ AC_CHECK_HEADERS(
        netdb.h \
        netinet/in.h \
        net/if.h \
+       errno.h \
+       stdbool.h \
        arpa/nameser.h \
        arpa/nameser_compat.h \
        arpa/inet.h,
@@ -369,6 +371,16 @@ fi
 AC_CHECK_TYPE(ssize_t, ,
    AC_DEFINE(ssize_t, int, [the signed version of size_t]))
 
+# check for bool type
+AC_CHECK_TYPE([bool],[
+  AC_DEFINE(HAVE_BOOL_T, 1,
+    [Define to 1 if bool is an available type.])
+], ,[
+#ifdef HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+])
+
 # Check for socklen_t or equivalent
 CURL_CHECK_TYPE_SOCKLEN_T
 

setup_once.h

@@ -62,6 +62,10 @@
 #include <fcntl.h>
 #endif
 
+#ifdef HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+
 
 /*
  * Definition of timeval struct for platforms that don't have it.
@@ -176,6 +180,28 @@ struct timeval {
                           (((unsigned char)x) == '\t'))
 
 
+/*
+ * Typedef to 'unsigned char' if bool is not an available 'typedefed' type.
+ */
+
+#ifndef HAVE_BOOL_T
+typedef unsigned char bool;
+#define HAVE_BOOL_T
+#endif
+
+
+/*
+ * Default definition of uppercase TRUE and FALSE.
+ */
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+
 /*
  * Typedef to 'int' if sig_atomic_t is not an available 'typedefed' type.
  */