Do not check that the compiler supports implicit ints without errors.
Add a missing #include <unistd.h>.
Submitted upstream: <https://github.com/fvwmorg/fvwm/pull/100>
diff --git a/acinclude.m4 b/acinclude.m4
index 8b74ff1e5be21f6d..4dee2abebc678358 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -30,7 +30,7 @@ if test "$ac_cv_func_select" = yes; then
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif],
-[extern select ($ac_cv_type_fd_set_size_t,
+[extern int select ($ac_cv_type_fd_set_size_t,
$ac_cv_type_fd_set *, $ac_cv_type_fd_set *, $ac_cv_type_fd_set *,
$ac_type_timeval *);],
[ac_found=yes ; break 3],ac_found=no)
@@ -1154,6 +1154,9 @@ AC_DEFUN([AM_SAFETY_CHECK_MKSTEMP],[
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
int main(void)
{
char template[128];
diff --git a/configure.ac b/configure.ac
index 1389d5643653aa8e..cd73b925dc077141 100644
--- a/configure.ac
+++ b/configure.ac
@@ -220,7 +220,7 @@ AC_MINIX
# catch -Werror and similar options when running configure
AC_TRY_COMPILE([#include <stdio.h>],
-[int i; static j; int *p; char *c;
+[int i; int *p; char *c;
switch (*p = p = *c) { case 0: printf("%Q", c, p); }
*c = &i; c = p;
while (1 || (unsigned int)3 >= 0 || ((int)-1) == ((unsigned int)1));