Do not set feature test macro in public header

We believe that this should be set by applications rather than by the
library. The spec suggests that having it in this spot is not correct as
it should be set prior to any header being included. See
https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_02.

Fixes #318

Changes.md

@@ -1,7 +1,10 @@
-## 1.7.2
+## 1.8.0
 
 * `PACKAGE_VERSION` is now a private compile definition when building
   with CMake. Pull request by bsergean. GitHub #308.
+* The feature macro `_POSIX_C_SOURCE` is no longer set by `maxminddb.h`. As
+  discussed in GitHub #318, this should be set by applications rather than
+  by libraries.
 
 ## 1.7.1 - 2022-09-30
 

bin/mmdblookup.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif

include/maxminddb.h

@@ -5,18 +5,6 @@ extern "C" {
 #ifndef MAXMINDDB_H
 #define MAXMINDDB_H
 
-/* Request POSIX.1-2008. However, we want to remain compatible with
- * POSIX.1-2001 (since we have been historically and see no reason to drop
- * compatibility). By requesting POSIX.1-2008, we can conditionally use
- * features provided by that standard if the implementation provides it. We can
- * check for what the implementation provides by checking the _POSIX_VERSION
- * macro after including unistd.h. If a feature is in POSIX.1-2008 but not
- * POSIX.1-2001, check that macro before using the feature (or check for the
- * feature directly if possible). */
-#ifndef _POSIX_C_SOURCE
-#define _POSIX_C_SOURCE 200809L
-#endif
-
 #include "maxminddb_config.h"
 #include <stdarg.h>
 #include <stdbool.h>

src/data-pool.c

@@ -1,3 +1,7 @@
+#ifdef TEST_DATA_POOL
+#define _POSIX_C_SOURCE 200809L
+#endif
+
 #include "data-pool.h"
 #include "maxminddb.h"
 

t/bad_databases_t.c

@@ -1,5 +1,6 @@
 // This test currently does not work on Windows as nftw is
 // not available.
+#define _POSIX_C_SOURCE 200809L
 #define _XOPEN_SOURCE 500
 #include <ftw.h>
 

t/bad_pointers_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void run_tests(int mode, const char *mode_desc) {

t/basic_lookup_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 static void test_big_lookup(void);

t/data-pool-t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "libtap/tap.h"
 #include "maxminddb_test_helper.h"
 #include <assert.h>

t/data_entry_list_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 MMDB_entry_data_list_s *

t/data_types_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void test_all_data_types(MMDB_lookup_result_s *result,

t/dump_t.c

@@ -1,4 +1,6 @@
+#define _POSIX_C_SOURCE 200809L
 #define _XOPEN_SOURCE 700
+
 #include "maxminddb_test_helper.h"
 
 #ifdef HAVE_OPEN_MEMSTREAM

t/get_value_pointer_bug_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 /* This test exercises a bug found in MMDB_get_value for certain types of

t/get_value_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void test_array_0_result(int status,

t/ipv4_start_cache_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void test_one_ip(MMDB_s *mmdb,

t/ipv6_lookup_in_ipv4_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void run_tests(int mode, const char *mode_desc) {

t/metadata_pointers_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void run_tests(int mode, const char *mode_desc) {

t/metadata_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void test_metadata(MMDB_s *mmdb, const char *mode_desc) {

t/no_map_get_value_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void run_tests(int mode, const char *mode_desc) {

t/read_node_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 void test_entry_data(MMDB_s *mmdb,

t/threads_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 #include <pthread.h>
 

t/version_t.c

@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+
 #include "maxminddb_test_helper.h"
 
 int main(void) {