Cygwin: testsuite: avoid "conflicting types" gcc warning
With gcc 11.2:
test.h:50:5: warning: conflicting types for built-in function ‘execve’; expected ‘int(const char *, char * const*)’ [-Wbuiltin-declaration-mismatch]
test.h:51:5: warning: conflicting types for built-in function ‘execv’; expected ‘int(const char *, char * const*)’ [-Wbuiltin-declaration-mismatch]
test.h:52:5: warning: conflicting types for built-in function ‘execvp’; expected ‘int(const char *, char * const*)’ [-Wbuiltin-declaration-mismatch]
Fix prototypes accordingly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
d5cc66426b