posix_spawn issues on i686

[Jeremy Drake]

>From https://github.com/msys2/MSYS2-packages/issues/2801

MSYS2 recently rebuilt GNU make 4.3, and I found that after rebuilding, it
broke rather horribly on i686, where any attempt to run a command resulted
in "Invalid argument" errors.  Some debugging revealed that rebuilding
make resulted in it using posix_spawn now instead of vfork.  Passing
--disable-posix-spawn to make's configure script results in a working i686
make.

>From the MSYS2 bug report:

"""
For reference, I tried to rebuild "make" in cygwin 32 bit and it has the
same problem:

rebuilding cygport make.cygport all results in a broken make
Adding CYGCONF_ARGS="--disable-posix-spawn" to the cygport file and
rebuilding again results in a good make
A Makefile to reproduce the issue:

all:
	echo hi
"""

In addition, make check fails rather horribly as well.

I know that 32-bit is on the way out, but it is concerning to me that
there is some latent bug lurking in this code path that is apparently not
well exercised.