posix_spawn tests: Fix link error on 64-bit Cygwin

[Bruno Haible]

This patch fixes a link error on 64-bit Cygwin, seen within
the 'gettext' package. It's related to and relies on
<https://lists.gnu.org/archive/html/bug-gnulib/2018-01/msg00087.html>.


2018-09-18  Bruno Haible  <address@hidden>

        posix_spawn tests: Fix link error on 64-bit Cygwin.
        * tests/test-posix_spawn1.c (environ): Remove declaration.
        * tests/test-posix_spawn2.c (environ): Likewise.
        * tests/test-posix_spawn3.c (environ): Likewise.
        * tests/test-posix_spawn4.c (environ): Likewise.
        * modules/posix_spawn-tests (Depends-on): Add 'environ'.
        * modules/posix_spawnp-tests (Depends-on): Likewise.

diff --git a/modules/posix_spawn-tests b/modules/posix_spawn-tests
index 8795206..55c4efd 100644
--- a/modules/posix_spawn-tests
+++ b/modules/posix_spawn-tests
@@ -9,6 +9,7 @@ posix_spawn_file_actions_destroy
 stdbool
 unistd
 sys_wait
+environ
 
 configure.ac:
 AC_EGREP_CPP([notposix], [[
diff --git a/modules/posix_spawnp-tests b/modules/posix_spawnp-tests
index 6363585..bce8be7 100644
--- a/modules/posix_spawnp-tests
+++ b/modules/posix_spawnp-tests
@@ -15,11 +15,12 @@ posix_spawnattr_init
 posix_spawnattr_setsigmask
 posix_spawnattr_setflags
 posix_spawnattr_destroy
-sigprocmask
 stdbool
 unistd
 sys_wait
 dup
+environ
+sigprocmask
 
 configure.ac:
 AC_EGREP_CPP([notposix], [[
diff --git a/tests/test-posix_spawn1.c b/tests/test-posix_spawn1.c
index fad0237..6b6c864 100644
--- a/tests/test-posix_spawn1.c
+++ b/tests/test-posix_spawn1.c
@@ -53,8 +53,6 @@ SIGNATURE_CHECK (posix_spawn_file_actions_adddup2, int,
 #include <sys/types.h>
 #include <sys/wait.h>
 
-extern char **environ;
-
 #define CHILD_PROGRAM_FILENAME "test-posix_spawn1.sh"
 
 static int
diff --git a/tests/test-posix_spawn2.c b/tests/test-posix_spawn2.c
index ed9567a..d9f29a1 100644
--- a/tests/test-posix_spawn2.c
+++ b/tests/test-posix_spawn2.c
@@ -31,8 +31,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
-extern char **environ;
-
 #define CHILD_PROGRAM_FILENAME "test-posix_spawn2.sh"
 
 static int
diff --git a/tests/test-posix_spawn3.c b/tests/test-posix_spawn3.c
index 1d5c47f..c35bd97 100644
--- a/tests/test-posix_spawn3.c
+++ b/tests/test-posix_spawn3.c
@@ -38,8 +38,6 @@ SIGNATURE_CHECK (posix_spawn, int, (pid_t *, char const *,
 #include <sys/types.h>
 #include <sys/wait.h>
 
-extern char **environ;
-
 #define CHILD_PROGRAM_FILENAME "test-posix_spawn3"
 #define DATA_FILENAME "t!#$%&'()*+,-;address@hidden|}~.tmp"
 /* On Cygwin, '*' '?' '\\' '|' cannot be used in file names.  */
diff --git a/tests/test-posix_spawn4.c b/tests/test-posix_spawn4.c
index 79308b9..14b29fb 100644
--- a/tests/test-posix_spawn4.c
+++ b/tests/test-posix_spawn4.c
@@ -31,8 +31,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
-extern char **environ;
-
 static int
 fd_safer (int fd)
 {