crt: tests: update t_main_assert

It is unclear what is the purpose of t_main_assert; it could be a simple
test program to observe behavior of assert() in an application using `main`
as the entry point.

On Windows, `main` usually recieves at least one argument (argv[0]) which is
the absolute filename of the executable.

Update this test to check this assumption.

Add t_main_assert to testcases/Makefile.am.

Signed-off-by: Kirill Makurin <maiddaisuki@outlook.com>
Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-crt/testcases/Makefile.am

diff --git a/mingw-w64-crt/testcases/Makefile.am b/mingw-w64-crt/testcases/Makefile.am
index ea1e728..bea64c0 100644
--- a/mingw-w64-crt/testcases/Makefile.am
+++ b/mingw-w64-crt/testcases/Makefile.am
@@ -49,6 +49,7 @@
   t_lfs \
   t_lseeki64 \
   t_main \
+  t_main_assert \
   t_main_cpp \
   t_matherr \
   t_mbrlen \

mingw-w64-crt/testcases/t_main_assert.c

diff --git a/mingw-w64-crt/testcases/t_main_assert.c b/mingw-w64-crt/testcases/t_main_assert.c
index 5200b48..0c0a3ff 100644
--- a/mingw-w64-crt/testcases/t_main_assert.c
+++ b/mingw-w64-crt/testcases/t_main_assert.c
@@ -9,8 +9,8 @@
 
 int main(int argc, char **argv)
 {
-  printf ("Is argc (%d) < 3 ?\n", argc);
-  assert (argc < 3);
-  printf ("No assert !\n");
+  assert (argc >= 1);
+  assert (argv != NULL);
+  assert (argv[0] != NULL);
   return 0;
 }