cond tests: fix compilation error on Solaris

[Bruno Haible]

A testdir for 'cond' fails to compile on Solaris 10:

gcc -O2 -DHAVE_CONFIG_H -I. -I../../gltests -I.. -DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I../../gltests -I.. -I../../gltests/.. -I../gllib -I../../gltests/../gllib -I/home/haible/prefix-x86/include -Wall -D_REENTRANT -g -O2 -MT test-cond.o -MD -MP -MF .deps/test-cond.Tpo -c -o test-cond.o ../../gltests/test-cond.c
In file included from ./unistd.h:40:0,
from ../../gltests/test-cond.c:61:
/usr/include/unistd.h:542:23: error: macro "yield" passed 1 arguments, but takes just 0
extern void yield(void);
^
*** Error code 1

The reason is that on Solaris, <unistd.h> declares yield(), which we have
defined as a macro in this compilation unit. This patch fixes it.


2018-05-10 Bruno Haible <***@clisp.org>

cond tests: Fix compilation error on Solaris.
* tests/test-cond.c: Include <unistd.h> before defining 'yield' as a
macro.

diff --git a/tests/test-cond.c b/tests/test-cond.c
index d2bf560..658596f 100644
--- a/tests/test-cond.c
+++ b/tests/test-cond.c
@@ -36,6 +36,7 @@
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
+#include <unistd.h>

#include "glthread/cond.h"
#include "glthread/lock.h"
@@ -58,7 +59,6 @@
/*
* Condition check
*/
-#include <unistd.h>
static int cond_value = 0;
gl_cond_define_initialized(static, condtest)
gl_lock_define_initialized(static, lockcond)