Use explicit instead of autoconfigured Bazel CROSSTOOL.

[david-german-tri]

This change is 

[david-german-tri]

@drake-jenkins-bot linux-gcc-bazel-experimental please

[david-german-tri]

@drake-jenkins-bot retest this please

[david-german-tri]

@drake-jenkins-bot retest this please

[david-german-tri]

-(status: do not merge) -(status: do not review) +@jwnimmer-tri for both levels of review

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Review status: 0 of 7 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[david-german-tri]

Most of the LOC in this PR are third_party imports, either from the Bazel source tree, or from the outputs of cc_configure.bzl on our supported platforms: https://github.com/bazelbuild/bazel/blob/master/tools/cpp/cc_configure.bzl

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Review status: 0 of 7 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[jwnimmer-tri]

Checkpoint.

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Reviewed 6 of 7 files at r1.
Review status: 6 of 7 files reviewed at latest revision, 2 unresolved discussions.

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drake/doc/bazel.rst, line 52 at r1 (raw file):

  bazel test //...                      # Build and test the entire project.
  bazel build --compiler=gcc-4.9 //...  # Build using gcc 4.9 on Trusty.
  bazel build --compiler=gcc-5 //...    # Build using gcc 5.x on Xenial.

Does this PR need to coincide with a drake-ci configuration change as well, then?

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tools/third_party/bazel/tools/cpp/osx_cc_wrapper.sh, line 1 at r1 (raw file):

#!/bin/bash

BTW Is this file pristine, or modified in Drake vs Bazel? If the latter, please rebase the commits so that the pristine vendor copy comes it in its own commit, and our diffs are separated out.

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Comments from Reviewable

[david-german-tri]

Review status: 6 of 7 files reviewed at latest revision, 2 unresolved discussions.

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drake/doc/bazel.rst, line 52 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

Does this PR need to coincide with a drake-ci configuration change as well, then?

Yes, #4920

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tools/third_party/bazel/tools/cpp/osx_cc_wrapper.sh, line 1 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

BTW Is this file pristine, or modified in Drake vs Bazel? If the latter, please rebase the commits so that the pristine vendor copy comes it in its own commit, and our diffs are separated out.

It's pristine.

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Comments from Reviewable

[jwnimmer-tri]

Reviewed 1 of 7 files at r1.
Review status: all files reviewed at latest revision, 2 unresolved discussions.

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tools/CROSSTOOL, line 1 at r1 (raw file):

# This CROSSTOOL was produced by copying the Bazel auto-generated CROSSTOOL for

Please add a comment explaining how to re-run or re-create this step.

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tools/CROSSTOOL, line 2 at r1 (raw file):

# This CROSSTOOL was produced by copying the Bazel auto-generated CROSSTOOL for
# our supported platforms, and then making some Drake-specific tweaks.

BTW At least some tweaks are marked "specific to Drake". Are they all marked as such? Might be a good idea -- and then if so, explain that marking here.

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Comments from Reviewable

[jwnimmer-tri]

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Review status: all files reviewed at latest revision, 2 unresolved discussions.

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Comments from Reviewable

[david-german-tri]

Review status: 6 of 7 files reviewed at latest revision, 2 unresolved discussions.

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tools/CROSSTOOL, line 1 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

Please add a comment explaining how to re-run or re-create this step.

Done.

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tools/CROSSTOOL, line 2 at r1 (raw file):

Previously, jwnimmer-tri (Jeremy Nimmer) wrote…

BTW At least some tweaks are marked "specific to Drake". Are they all marked as such? Might be a good idea -- and then if so, explain that marking here.

Done.

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Comments from Reviewable