The test in link.m4 needs to include <stdio.h> to provide a declaration
for the rename function. The test fails if building with GCC's
-Werror=implicit-function-declaration option.
This was reported as part of a bug with building Octave on Fedora, which
now uses -Werror=implicit-function-declaration by default.
https://savannah.gnu.org/bugs/?49782
jwe
diff -up octave-4.2.0/m4/link.m4.implicit octave-4.2.0/m4/link.m4
--- octave-4.2.0/m4/link.m4.implicit 2016-11-13 08:21:54.000000000 -0700
+++ octave-4.2.0/m4/link.m4 2016-12-06 13:52:47.132003993 -0700
@@ -22,6 +22,7 @@ AC_DEFUN([gl_FUNC_LINK],
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
+ #include <stdio.h>
]],
[[int result = 0;
if (!link ("conftest.a", "conftest.b/"))
