Add configure check for gettid() presence

The gettid() function is available on Linux in glibc only since version
2.30. There are supported distributions that still use older glibc
version. Thus add a configure check if the gettid() function is
available and extend the check in src/prof_stack_range.c so it's skipped
also when gettid() isn't available.

Fixes: https://github.com/jemalloc/jemalloc/issues/2740

configure.ac

@@ -2706,6 +2706,15 @@ if test "x${je_cv_pthread_mutex_adaptive_np}" = "xyes" ; then
   AC_DEFINE([JEMALLOC_HAVE_PTHREAD_MUTEX_ADAPTIVE_NP], [ ], [ ])
 fi
 
+JE_COMPILABLE([gettid], [
+#include <unistd.h>
+], [
+  int tid = gettid();
+], [je_cv_gettid])
+if test "x${je_cv_gettid}" = "xyes" ; then
+  AC_DEFINE([JEMALLOC_HAVE_GETTID], [ ], [ ])
+fi
+
 JE_CFLAGS_SAVE()
 JE_CFLAGS_ADD([-D_GNU_SOURCE])
 JE_CFLAGS_ADD([-Werror])

src/prof_stack_range.c

@@ -4,7 +4,7 @@
 #include "jemalloc/internal/malloc_io.h"
 #include "jemalloc/internal/prof_sys.h"
 
-#if defined (__linux__)
+#if defined (__linux__) && defined(JE_HAVE_GETTID)
 
 #include <errno.h>
 #include <fcntl.h>