Improve BSD compatibility of contrib/install_db4.sh #11945

This PR improves the BSD compatibility of the bdb4 installer script.

See #11921, #11868.

I've tested this on OpenBSD 6.2 (clang) and Ubuntu 16.04 (gcc).

This needs testing on OSX at least, and on gcc/Linux to make sure that applying the patch unconditionally doesn't negatively affect gcc.

NB: this is not yet sufficient to make install_db4.sh work on FreeBSD, as we need to use yet another sha256 tool there. But it's a step in the right direction.

contrib: New clang patch for install_db4

Replace the clang patch with a new and improved version that also fixes the build issues with OpenBSD and FreeBSD's clang, and apply it unconditionally.

Thanks to @fanquake for finding the patch.

contrib: Make X=Y arguments work in install_db4

Trailing X=Y arguments are supposed to be passed through unchanged to bdb's configure. This was not the case, at least with OpenBSD 6.2's shell.

Fix this by not storing the arguments in a temporary variable but passing "$@" through directly.

contrib: FreeBSD compatibility in install_db4.sh

Unfortunately, FreeBSD uses yet another syntax for sha256.

Support FreeBSD's syntax too. Using uname is a bit of a hack but it works and I found no way to distinguish the two.

I've tested on OS X and OpenBSD 6.2, using this commit on top of 1fb34e0d1f585dc6bb26ccbbcc26e9be4e107892, plus some of the changes to install instructions in other open PRs.

The new patch should be ok, because it's doing the same thing we do when patching bd4 in depends.

note: Should we bring this patch into depends, and then we can use it from there for this script?

testedACK c0298b0

Added a commit that adds FreeBSD compatibility! (and shortened the build instructions with it)

Tested on MacOS 10.13.2, with most dependencies installed via Homebrew (berkeley-db4 in particular):

./autogen
./configure

Configure summary:

Options used to compile and link:
  with wallet   = yes
  with gui / qt = yes
    qt version  = 5
    with qr     = yes
  with zmq      = yes
  with test     = yes
  with bench    = yes
  with upnp     = yes
  use asm       = yes
  debug enabled = no
  werror        = no

  target os     = darwin
  build os      = darwin

  CC            = /usr/local/bin/ccache gcc
  CFLAGS        = -g -O2
  CPPFLAGS      = -Qunused-arguments  -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS -I/usr/local/opt/berkeley-db@4/include -DMAC_OSX
  CXX           = /usr/local/bin/ccache g++ -std=c++11
  CXXFLAGS      = -g -O2 -Wall -Wextra -Wformat -Wvla -Wformat-security -Wthread-safety-analysis -Wno-unused-parameter -Wno-self-assign -Wno-unused-local-typedef -Wno-deprecated-register -Wno-implicit-fallthrough
  LDFLAGS       =  -Wl,-headerpad_max_install_names -Wl,-dead_strip
  ARFLAGS       = cr

make

make is happy, but I did notice this (not sure if that's new):

  CXX      leveldb/util/leveldb_libleveldb_a-histogram.o
  CXX      leveldb/util/leveldb_libleveldb_a-logging.o
leveldb/util/logging.cc:58:40: warning: comparison of integers of different signs: 'const int' and 'unsigned long long' [-Wsign-compare]
          (v == kMaxUint64/10 && delta > kMaxUint64%10)) {
                                 ~~~~~ ^ ~~~~~~~~~~~~~
1 warning generated.
  CXX      leveldb/util/leveldb_libleveldb_a-options.o
  CXX      leveldb/util/leveldb_libleveldb_a-status.o
  CXX      leveldb/port/leveldb_libleveldb_a-port_posix.o
  AR       leveldb/libleveldb.a

make check
test/functional/test_runner.py
make deploy

All tests pass with the exception of rawtransactions.py (logs), unrelated?

I can see my transactions in BitcoinQT.

Thanks for testing!

All tests pass with the exception of rawtransactions.py (logs), unrelated?

Yes, expected: that's the problem fixed in #11947. This PR was branched off before that (note that travis doesn't flag it). The leveldb warning is old, and also unrelated.

utACK https://github.com/bitcoin/bitcoin/pull/11945/commits/2712742ef2947feef4a142f7d1360d1e821597dc

utACK 2712742ef2947feef4a142f7d1360d1e821597dc

re-ACK 2712742