lib: sgp4: fix strtok_r availability on native_sim

Define `_POSIX_C_SOURCE 200809L` in `sgp4_pass_predict.c` to make
`strtok_r` available via picolibc without needing a manual forward
declaration. Remove the now-redundant `strtok_r` declarations from
the test files.

Signed-off-by: Simen S. Røstad <simen.rostad@nordicsemi.no>

Author: simensrostad

lib/sgp4/sgp4_pass_predict.c

@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
+#ifdef _POSIX_C_SOURCE
+#undef _POSIX_C_SOURCE
+#endif
+/* Required for strtok_r() on native_sim / picolibc. */
+#define _POSIX_C_SOURCE 200809L
+
 #include <string.h>
 #include <stdint.h>
 #include <stdlib.h>

tests/lib/ntn-sib32/src/test_sib32_tle.c

@@ -17,8 +17,6 @@
 
 /* missing headers */
 struct tm *gmtime_r(const int64_t *timep, struct tm *result);
-char *strtok_r(char *str, const char *delim, char **saveptr);
-
 
 DEFINE_FFF_GLOBALS;
 

tests/lib/ntn/src/sgp4_pass_test.c

@@ -17,8 +17,6 @@
 
 /* missing headers */
 struct tm *gmtime_r(const int64_t *timep, struct tm *result);
-char *strtok_r(char *str, const char *delim, char **saveptr);
-
 
 DEFINE_FFF_GLOBALS;