rustdoc: a lot of test causes OS Error 8 on Win32

[klutzy]

for i in range(200):
    print "/// ```"
    print "/// assert!(1u == 1u);"
    print "/// ```"
    print "fn dummy_" + str(i) + "() {}"

$ python gen.py > lib.rs
$ rustdoc.exe --test lib.rs

<snip>

failures:

---- dummy_79_0 stdout ----
        error: could not exec the linker `gcc`: OS Error 8: <os-specific message>

        error: aborting due to previous error
        task 'dummy_79_0' failed at 'Box<Any>', C:\home\stone\rust\src\libsyntax\ast_util.rs:776

<snip>

test result: FAILED. 173 passed; 27 failed; 0 ignored; 0 measured

(The number of failures vary)

I met this during check-stage2-T-i686-pc-mingw32-H-i686-pc-mingw32-doc-crate-std.

[huonw]

This is possibly due to spawning too many rustc processes (I assume it's currently spawning one for each code block all at the same time?).

[alexcrichton]

It looks like error 8 is OOM, is there anything we can really do about that? Does your system have an adequate amount of memory to run all these tests in parallel?

[klutzy]

I've checked there was sufficient memory and the failure occurred even if RUST_TEST_TASKS=1 is given.
Well, however I'm failing to reproduce the error now.. so let's close this until real reason is found ¯_(ツ)_/¯