Make poll() test work with gcc 14

Fixes erlang#9211

* Add headers (`stdlib.h`, `fcntl.h`) for `poll`
* Add `unistd.h` for `sbrk`

erts/config.h.in

@@ -438,6 +438,9 @@
 /* Define if x86/x86_64 out of order instructions should be synchronized */
 #undef ETHR_X86_OUT_OF_ORDER
 
+/* Define to 1 if _Float16 can be converted from/to double. */
+#undef FLOAT16_IS_CONVERTIBLE
+
 /* Define to 1 if you have the <arpa/nameser.h> header file. */
 #undef HAVE_ARPA_NAMESER_H
 

erts/configure

@@ -19754,6 +19754,37 @@ printf "%s\n" "#define SIZEOF__FLOAT16 $ac_cv_sizeof__Float16" >>confdefs.h
 
 
 
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+_Float16 x = 0.0;
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for _Float16 convertible" >&5
+printf %s "checking for _Float16 convertible... " >&6; }
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+
+printf "%s\n" "#define FLOAT16_IS_CONVERTIBLE 1" >>confdefs.h
+
+
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for _Float16 convertible" >&5
+printf %s "checking for _Float16 convertible... " >&6; }
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+	 ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+
 BITS64=
 
 if test $ac_cv_sizeof_void_p = 8; then
@@ -21702,6 +21733,7 @@ else case e in #(
 /* end confdefs.h.  */
 
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef HAVE_MALLOC_H
 #  include <malloc.h>
 #endif
@@ -25891,8 +25923,10 @@ else case e in #(
   e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <fcntl.h>
 #include <poll.h>
-main()
+#include <stdlib.h>
+int main()
 {
 #ifdef _POLL_EMUL_H_
   exit(1); /* Implemented using select() -- fail */

erts/configure.ac

@@ -2443,6 +2443,7 @@ AC_CACHE_CHECK([if __after_morecore_hook can track malloc()s core memory use],
 		erts_cv___after_morecore_hook_can_track_malloc,
 		[AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef HAVE_MALLOC_H
 #  include <malloc.h>
 #endif
@@ -3137,8 +3138,10 @@ poll_works=no
 [
 
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <fcntl.h>
 #include <poll.h>
-main()
+#include <stdlib.h>
+int main()
 {
 #ifdef _POLL_EMUL_H_
   exit(1); /* Implemented using select() -- fail */