bootstrap.sh bugfixes and sh compat

1. Assign the var and export afterwards.

2. Use mktemp instead of home-grown solution. The mktemp flags we use
   are supported on FreeBSD, Solaris, OpenBSD, and Linux.

The order of the 2>&1 and the redirect matters. The 2>&1 has to be last.

Don't use variables in the printf format string.
Use printf "..%s.." "$foo".

This avoids the need to cd back.

This catches if cd fails and also avoid the need to cd .. back.

Note that A && B || C is not if-then-else. C may run when A is true.

Fix handling of default setup deps

Covers 3 of the 4 possible cases:
1. explicit custom setup deps
2. custom setup with implicit/default deps
4. non-custom setup using the internal cabal lib version

case 3 is a non-custom setup but where we're forced to use an external
cabal lib version. This case is hard to test since it only happens when
it's a newer (not older) Cabal lib version that the package requires,
e.g. a .cabal file that specifies cabal-version: >= 2.0.

Also, add a --with-ghc option to the integration test suite, which lets us
more easily test with different ghc versions.

Also, don't use parallel builds in any of the integration tests, as the
self-exec method will not work, and some tests need to install deps for
some ghc versions.

haddock/hscolour: fix highlighted source location

When generating haddocks with the `--for-hackage` switch, the generated
haddocks are placed in a different directory than the normal ones, which
includes the package id instead of just the package name. When we ran
hscolour, we didn't respect this, so the highlighted source would not
be placed in the correct directory and thus was missing from the tarball.
This patch fixes that.

Fixes #3451

travis-script.sh: fix POSIX and sh compat

Updated --package-db docs

There is also information on how to reset the stack.

Resolve #2345

* remove bashisms
* fix POSIX compliance
* change shebang to /bin/sh

Implement -j in travis and bootstrap script

bootstrap.sh: fix duplicate GHC_VER definition

No need to install cabal-install package

[ci skip]

Now that we bootstrap Cabal and cabal-install, we don't have to install
the package anymore.

[ci skip]

[ci skip]

Anders Kaseorg authored 8 years ago and Mikhail Glushenkov committed 8 years ago

GHC 7.8 renamed "Gcc Linker flags" to "C compiler link flags" and "Ld
Linker flags" to "ld flags"
(https://ghc.haskell.org/trac/ghc/ticket/4862

).

Without this corresponding fix in Cabal, the old-time package fails to
compile on Ubuntu yakkety amd64, where the system GCC now defaults to
-pie and GHC has

    $ ghc --info | grep -i pie
     ,("C compiler flags","-fno-PIE -fno-stack-protector")
     ,("C compiler link flags","-no-pie")
     ,("ld flags","-no-pie")

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
(cherry picked from commit c993a0c6)

[ci skip]

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Try using smaller package ids on Windows (see #3430)

Commit 2f976576 added default setup dep
handling to the existing install command code paths, but unfortunately
broke the handling for the new-build code path. It added a call to
addDefaultSetupDependencies into the standardInstallPolicy. That
interfered with the addDefaultSetupDependencies that ProjectPlanning was
already using.

So this patch splits a basicInstallPolicy out of standardInstallPolicy,
where the basicInstallPolicy is all the old stuff, and the
standardInstallPolicy just adds the addDefaultSetupDependencies that the
install/fetch/freeze commands need. So then ProjectPlanning uses just
the basicInstallPolicy.

The 2f976576 commit also added a new and simpler method to determine if a
package has had default setup deps added. Previously ProjectPlanning had
to use a rather complex method to remember this information. So this
patch removes all that and makes use of the new method.

To stop this breaking in future the next patch adds integration tests to
cover custom setup script handling.

This fixed issue #3394.