to define main with arguments, for C++. Reported by Eric Blake.
* c-stack.m4 (AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC):
Prefer 'int main ()' to 'int main (void)', for C++.
* getcwd-path-max.m4 (gl_FUNC_GETCWD_PATH_MAX): Likewise.
* fsusage.m4 (gl_FILE_SYSTEM_USAGE): Specify a return type
for 'main', for C99 and C++.
to 1MB, so as not to render systems with no stack size limit (e.g.,
linux-2.2.x) unusable. Suggestion and code from Bruno Haible.
Include <unistd.h>. On some systems,
it is required for the definition of _SC_PAGESIZE.
