ed1bbcefea contrib: add MACHO tests to symbol-check tests (fanquake)
5bab08df17 contrib: Add test for ELF symbol-check (Wladimir J. van der Laan)
Pull request description:
Check both failure cases:
- Use a glibc symbol from a version that is too new
- Use a symbol from a library that is not in the allowlist
And also check a conforming binary.
Adding a similar check for Windows PE can be done in a separate PR.
ACKs for top commit:
fanquake:
ACK ed1bbcefea
Tree-SHA512: fd437612e003922465fe1396efa1fa3a64bd1c7b0a514d2a0a7a0caaaa9fb5cb43e0ed7caec15eb0a3508692c9eb3212d7ba3c7e8180b942dd3e50616ad6e557
faa05854f8 util: Remove probably misleading TODO (MarcoFalke)
fac5efe730 util: Add Assume() identity function (MarcoFalke)
fa861569dc util: Allow Assert(...) to be used in all contexts (practicalswift)
Pull request description:
This is needed for #20138. Please refer to the added documentation for motivation.
ACKs for top commit:
practicalswift:
cr ACK faa05854f8
jnewbery:
utACK faa05854f8
hebasto:
ACK faa05854f8, I have reviewed the code and it looks OK, I agree it can be merged.
Tree-SHA512: 72165fbd898b92ab9a79b070993fa1faa86c2e3545b6645e72c652bda295d5107bc298d0482bf3aaf0926fc0c3e6418a445c0e073b08568c44231f547f76a688
Check both failure cases:
- Use a glibc symbol from a version that is too new
- Use a symbol from a library that is not in the allowlist
And also check a conforming binary.
Adding a similar check for Windows PE can be done in a separate PR.
d52f502b1e Fix mock SQLiteDatabases (Andrew Chow)
99309ab3e9 Allow disabling BDB in configure with --without-bdb (Andrew Chow)
ee47f11f73 GUI: Force descriptor wallets when BDB is not compiled (Andrew Chow)
71e40b33bd RPC: Require descriptors=True for createwallet when BDB is not compiled (Andrew Chow)
6ebc41bf9c Enforce salvage is only for BDB wallets (Andrew Chow)
a58b719cf7 Do not compile BDB things when USE_BDB is defined (Andrew Chow)
b33af48210 Include wallet/bdb.h where it is actually being used (Andrew Chow)
Pull request description:
Adds a `--without-bdb` option to `configure` which disables the compilation of the BDB stuff. Legacy wallets will not be created when BDB is not compiled. A legacy-sqlite wallet can be loaded, but we will not create them.
Based on #20156 to resolve the situation where both `--without-sqlite` and `--without-bdb` are provided. In that case, the wallet is disabled and `--disable-wallet` is effectively set.
ACKs for top commit:
laanwj:
Code review ACK d52f502b1e
Tree-SHA512: 5a92ba7a542acc2e27003e9d4e5940e0d02d5c1f110db06cdcab831372bfd83e8d89c269caff31dd5bff062c1cf5f04683becff12bd23a33be731676f346553d
8f7b930475 Drop the leading 0 from the version number (Andrew Chow)
Pull request description:
Removes the leading 0 from the version number. The minor version, which we had been using as the major version, is now the major version. The revision, which we had been using as the minor version, is now the minor version. The revision number is dropped. The build number is promoted to being part of the version number. This also avoids issues where it was accidentally not included in the version number.
The CLIENT_VERSION remains the same format as previous as previously, as the Major version was 0 so it never actually got included in it.
The user agent string formatter is updated to follow this new versioning.
***
Honestly I'm just tired of all of the people asking for "1.0" that maybe this'll shut them up. Skip the whole 1.0 thing and go straight to version 22.0!
Also, this means that the terminology we commonly use lines up with how the variables are named. So major versions are actually bumping the major version number, etc.
ACKs for top commit:
jnewbery:
Code review ACK 8f7b930475
MarcoFalke:
review ACK 8f7b930475🎻
Tree-SHA512: b5c3fae14d4c0a9c0ab3b1db7c949ecc0ac3537646306b13d98dd0efc17c489cdd16d43f0a24aaa28e9c4a92ea360500e05480a335b03f9fb308010cdd93a436
Removes the leading 0 from the version number. The minor version, which
we had been using as the major version, is now the major version. The
revision, which we had been using as the minor version, is now the minor
version. The revision number is dropped. The build number is promoted to
being part of the version number. This also avoids issues where it was
accidentally not included in the version number.
The CLIENT_VERSION remains the same format as previous as previously,
the Major version was 0 so that was never a factor in CLIENT_VERSION.
97c738ff1b [tests] Recommend f-strings for formatting, update feature_block to use them (Anthony Towns)
8ae9d314e9 Bump minimum python version to 3.6 (Anthony Towns)
Pull request description:
Python 3.5 has reached [end-of-life](https://devguide.python.org/#status-of-python-branches) as of September 2020, and 3.6 has some moderately nice [features](https://docs.python.org/3/whatsnew/3.6.html):
- `f'x = {x}'` as an alternative to `'x = {}'.format(x)` format strings (cf https://github.com/bitcoin/bitcoin/pull/13718#issuecomment-406591027)
- underscore separators for large numbers, like `1_234_567`
- improvements to async
- improvements to typing module
Note that 3.6 is not available in xenial (16.04), but is available in bionic (18.04), while focal (20.04) has 3.8. CentOS 7 and 8 have 3.6.8, Debian stable has 3.7.3, and [gentoo and arch already had 3.6 and 3.7 in 2018](https://github.com/bitcoin/bitcoin/pull/14954#issuecomment-447118707).
ACKs for top commit:
MarcoFalke:
re-ACK 97c738ff1b
Tree-SHA512: ec7fce68845edde4d61a42de12c065fd49e5217311a6fda1323206f091a0afd50f293645dffc27d420127e4e5deb864e953f1b67eff735a0dfbbedd7899a9d60
0e2a5e448f tests: dumping and minimizing of script assets data (Pieter Wuille)
4567ba034c tests: add generic qa-asset-based script verification unit test (Pieter Wuille)
f06e6d0345 tests: functional tests for Schnorr/Taproot/Tapscript (Pieter Wuille)
3c226639eb tests: add BIP340 Schnorr signature support to test framework (Pieter Wuille)
206fb180ec --- [TAPROOT] Tests --- (Pieter Wuille)
d7ff237f29 Activate Taproot/Tapscript on regtest (BIP 341, BIP 342) (Pieter Wuille)
e9a021d7e6 Make Taproot spends standard + policy limits (Pieter Wuille)
865d2c37e2 --- [TAPROOT] Regtest activation and policy --- (Pieter Wuille)
72422ce396 Implement Tapscript script validation rules (BIP 342) (Johnson Lau)
330de894a9 Use ScriptExecutionData to pass through annex hash (Pieter Wuille)
8bbed4b7ac Implement Taproot validation (BIP 341) (Pieter Wuille)
0664f5fe1f Support for Schnorr signatures and integration in SignatureCheckers (BIP 340) (Pieter Wuille)
5de246ca81 Implement Taproot signature hashing (BIP 341) (Johnson Lau)
9eb590894f Add TaggedHash function (BIP 340) (Pieter Wuille)
450d2b2371 --- [TAPROOT] BIP340/341/342 consensus rules --- (Pieter Wuille)
5d62e3a68b refactor: keep spent outputs in PrecomputedTransactionData (Pieter Wuille)
8bd2b4e784 refactor: rename scriptPubKey in VerifyWitnessProgram to exec_script (Pieter Wuille)
107b57df9f scripted-diff: put ECDSA in name of signature functions (Pieter Wuille)
f8c099e220 --- [TAPROOT] Refactors --- (Pieter Wuille)
Pull request description:
This is an implementation of the Schnorr/taproot consensus rules proposed by BIPs [340](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki), [341](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki), and [342](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki).
See the list of commits [below](https://github.com/bitcoin/bitcoin/pull/19953#issuecomment-691815830). No signing or wallet support of any kind is included, as testing is done entirely through the Python test framework.
This is a successor to https://github.com/bitcoin/bitcoin/pull/17977 (see discussion following [this comment](https://github.com/bitcoin/bitcoin/pull/17977#issuecomment-682285983)), and will have further changes squashed/rebased. The history of this PR can be found in #19997.
ACKs for top commit:
instagibbs:
reACK 0e2a5e448f
benthecarman:
reACK 0e2a5e4
kallewoof:
reACK 0e2a5e448f
jonasnick:
ACK 0e2a5e448f almost only looked at bip340/libsecp related code
jonatack:
ACK 0e2a5e448f modulo the last four commits (tests) that I plan to finish reviewing tomorrow
fjahr:
reACK 0e2a5e448f
achow101:
ACK 0e2a5e448f
Tree-SHA512: 1b00314450a2938a22bccbb4e177230cf08bd365d72055f9d526891f334b364c997e260c10bc19ca78440b6767712c9feea7faad9a1045dd51a5b96f7ca8146e
ba8950ee01 build: optionally skip external warnings (Vasil Dimov)
Pull request description:
Add an option to `./configure` to suppress compilation warnings from
external headers. The option is off by default (no change in behavior,
show warnings from external headers).
This option is useful if e.g. Boost or Qt is installed outside of
`/usr/include` (warnings from headers in `/usr/include` are already
suppressed by default) and those warnings stand in the way of compiling
Bitcoin Core with `-Werror[=...]` or they just clutter the build output
too much and make our own warnings hard to spot.
`-isystem /usr/include` bricks GCC's `#include_next`, so we use
`-idirafter` instead. This way we don't have to treat `/usr/include`
specially.
ACKs for top commit:
practicalswift:
ACK ba8950ee0134a7958e3e9b041cd54d222feb09a1: diff looks correct!
hebasto:
ACK ba8950ee01, tested on Linux Mint 20 (x86_64).
luke-jr:
utACK ba8950ee01
Tree-SHA512: 9b54fae8590be6c79f2688a5aca09e0a9067f481dabecdd49bb278c08a62ac2b0cc704c894fbd53240e77ac84da0c7a237845df0a696cfbdb0359e1c8e2e10c9
This enables the schnorrsig module in libsecp256k1, adds the relevant types
and functions to src/pubkey, as well as in higher-level `SignatureChecker`
classes. The (verification side of the) BIP340 test vectors is also added.
Add an option to `./configure` to suppress compilation warnings from
external headers. The option is off by default (no change in behavior,
show warnings from external headers).
This option is useful if e.g. Boost or Qt is installed outside of
`/usr/include` (warnings from headers in `/usr/include` are already
suppressed by default) and those warnings stand in the way of compiling
Bitcoin Core with `-Werror[=...]` or they just clutter the build output
too much and make our own warnings hard to spot.
c4b85ba704 Bugfix: Define and use HAVE_FDATASYNC correctly outside LevelDB (Luke Dashjr)
Pull request description:
Fixes a bug introduced in #19614
The LevelDB-specific fdatasync check was only using `AC_SUBST`, which works for Makefiles, but doesn't define anything for C++. Furthermore, the #define is typically 0 or 1, never undefined.
This fixes both issues by defining it and checking its value instead of whether it is merely defined.
Pulled out of #14501 by fanquake's request
ACKs for top commit:
fanquake:
ACK c4b85ba704 - thanks for catching and fixing my mistake.
laanwj:
Code review ACK c4b85ba704
Tree-SHA512: 91d5d426ba000b4f3ee7e2315635e24bbb23ceff16269ddf4f65a63d25fc9e9cf94a3b236eed2f8031cc36ddcf78aeb5916efcb244f415943a8a12f907ede8f9
b536813cef build: add -fstack-clash-protection to hardening flags (fanquake)
076183b36b build: add -fcf-protection=full to hardening options (fanquake)
Pull request description:
Beginning with Ubuntu `19.10`, it's packaged GCC now has some additional hardening options enabled by default (in addition to existing defaults like `-fstack-protector-strong` and reducing the minimum ssp buffer size). The new additions are`-fcf-protection=full` and `-fstack-clash-protection`.
> -fcf-protection=[full|branch|return|none]
> Enable code instrumentation of control-flow transfers to increase program security by checking that target addresses of control-flow transfer instructions (such as indirect function call, function return, indirect jump) are valid. This prevents diverting the flow of control to an unexpected target. This is intended to protect against such threats as Return-oriented Programming (ROP), and similarly call/jmp-oriented programming (COP/JOP).
> -fstack-clash-protection
> Generate code to prevent stack clash style attacks. When this option is enabled, the compiler will only allocate one page of stack space at a time and each page is accessed immediately after allocation. Thus, it prevents allocations from jumping over any stack guard page provided by the operating system.
If your interested you can grab `gcc-9_9.3.0-10ubuntu2.debian.tar.xz` from https://packages.ubuntu.com/focal/g++-9. The relevant changes are part of the `gcc-distro-specs` patches, along with the relevant additions to the gcc manages:
> NOTE: In Ubuntu 19.10 and later versions, -fcf-protection is enabled by default for C, C++, ObjC, ObjC++, if none of -fno-cf-protection nor -fcf-protection=* are found.
> NOTE: In Ubuntu 19.10 and later versions, -fstack-clash-protection is enabled by default for C, C++, ObjC, ObjC++, unless -fno-stack-clash-protection is found.
So, if you're C++ using GCC on Ubuntu 19.10 or later, these options will be active unless you explicitly opt out. This can be observed with a small test:
```c++
int main() { return 0; }
```
```bash
g++ --version
g++ (Ubuntu 9.3.0-10ubuntu2) 9.3.0
g++ test.cpp
objdump -dC a.out
..
0000000000001129 <main>:
1129: f3 0f 1e fa endbr64
112d: 55 push %rbp
112e: 48 89 e5 mov %rsp,%rbp
1131: b8 00 00 00 00 mov $0x0,%eax
1136: 5d pop %rbp
1137: c3 retq
1138: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
113f: 00
# recompile opting out of control flow protection
g++ test.cpp -fcf-protection=none
objdump -dC a.out
...
0000000000001129 <main>:
1129: 55 push %rbp
112a: 48 89 e5 mov %rsp,%rbp
112d: b8 00 00 00 00 mov $0x0,%eax
1132: 5d pop %rbp
1133: c3 retq
1134: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1)
113b: 00 00 00
113e: 66 90 xchg %ax,%ax
```
Note the insertion of an `endbr64` instruction when compiling and _not_ opting out. This instruction is part of the Intel Control-flow Enforcement Technology [spec](https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf), which the GCC control flow implementation is based on.
If we're still doing gitian builds for the `0.21.0` and `0.22.0` releases, we'd likely update the gitian image to Ubuntu Focal, which would mean that the GCC used for gitian builds would also be using these options by default. So we should decide whether we want to explicitly turn these options on as part of our hardening options (although not just for this reason), or, we should be opting-out.
GCC has supported both options since 8.0.0. Clang has supported `-fcf-protection` from 7.0.0 and will support `-fstack-clash-protection` in it's upcoming [11.0.0 release](https://clang.llvm.org/docs/ReleaseNotes.html#id6).
ACKs for top commit:
jamesob:
ACK b536813cef ([`jamesob/ackr/18921.1.fanquake.build_add_stack_clash_an`](https://github.com/jamesob/bitcoin/tree/ackr/18921.1.fanquake.build_add_stack_clash_an))
laanwj:
Code review ACK b536813cef
Tree-SHA512: abc9adf23cdf1be384f5fb9aa5bfffdda86b9ecd671064298d4cda0440828b509f070f9b19c88c7ce50ead9ff32afff9f14c5e78d75f01241568fbfa077be0b7
1ccb9f30c0 Move Win32 defines to configure.ac to ensure they are globally defined (Luke Dashjr)
Pull request description:
#9245 no longer needs this, since the main `_WIN32_WINNT` got bumped by something else.
So rather than just lose it, might as well get it merged in independently.
I'm not aware of any practical effects, but it seems safer to use the same API versions everywhere.
ACKs for top commit:
fanquake:
ACK 1ccb9f30c0 - checked that the binaries produced are the same.
Tree-SHA512: 273e9186579197be01b443b6968e26b9a8031d356fabc5b73aa967fcdb837df195b7ce0fc4e4529c85d9b86da6f2d7ff1bf56a3ff0cbbcd8cee8a9c2bf70a244
2f8a4c9a06 build: Enable some commonly enabled compiler diagnostics (practicalswift)
Pull request description:
Enable some commonly enabled compiler diagnostics as discussed in #17344.
| Compiler diagnostic | no# of emitted unique GCC warnings in `master` | no# of emitted unique Clang warnings in `master` |
| ------------- | ------------- | ------------- |
| `-Wduplicated-branches`: Warn if `if`/`else` branches have duplicated code | 0 | Not supported |
| `-Wduplicated-cond`: Warn if `if`/`else` chain has duplicated conditions | 0 | Not supported |
| `-Wlogical-op`: Warn about logical operations being used where bitwise were probably wanted | 0 | Not supported |
| `-Woverloaded-virtual`: Warn if you overload (not `override`) a virtual function | 0 | 0 |
| ~~`-Wunused-member-function`: Warn on unused member function~~ | Not supported | 2 |
| ~~`-Wunused-template`: Warn on unused template~~ | Not supported | 1 |
There is a large overlap between this list and [Jason Turner's list of recommended compiler diagnostics in the Collaborative Collection of C++ Best Practices (`cppbestpractices`) project](https://github.com/lefticus/cppbestpractices/blob/master/02-Use_the_Tools_Available.md#gcc--clang). There is also an overlap with the recommendations given in the [C++ Core Guidelines](https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines) (with editors Bjarne Stroustrup and Herb Sutter).
Closes#17344.
ACKs for top commit:
jonatack:
ACK 2f8a4c9a06 no warnings for me with these locally on debian 5.7.10-1 (2020-07-26) x86_64 with gcc 10 and clang 12
fanquake:
ACK 2f8a4c9a06 - no-longer seeing any obvious issues with doing this.
hebasto:
ACK 2f8a4c9a06, no new warnings in Travis jobs.
Tree-SHA512: f669ea22b31263a555f999eff6a9d65750662e95831b188c3192a2cf0127fb7b5136deb762a6b0b7bbdfb0dc6a40caf48251a62b164fffb81dd562bdd15ec3c8
70452a070b build: set minimum required Boost to 1.58 (fanquake)
Pull request description:
Any systems which only have an older installable Boost can use depends.
1.58.0 retains compatibility with the packages [installable on Ubuntu 16.04](https://packages.ubuntu.com/xenial/libboost-dev).
The projects usage of Boost wont be going away any time soon, if ever (i.e #15382), and our usage of the test framework.
Fixes: #19506
ACKs for top commit:
practicalswift:
ACK 70452a070b -- patch looks correct
laanwj:
ACK 70452a070b
hebasto:
ACK 70452a070b, tested on Linux Mint 20 (x86_64).
Tree-SHA512: d290415e3c70a394b3d7659c0480a35b4082bdce8d48b1c64a0025f7ad6e21567b4dc85813869513ad246d27f950706930410587c11c1aa3693ae6245084765c
This flag was added to binutils/ld in the 2.30 release,
see commit c11c786f0b45617bb8807ab6a57220d5ff50e414:
> The new "-z separate-code" option will generate separate code LOAD
segment which must be in wholly disjoint pages from any other data.
It was made the default for Linux/x86 targets in the 2.31 release, see commit
f6aec96dce1ddbd8961a3aa8a2925db2021719bb:
> This patch adds --enable-separate-code to ld configure to turn on
-z separate-code by default and enables it by default for Linux/x86.
This avoids mixing code pages with data to improve cache performance
as well as security.
> To reduce x86-64 executable and shared object sizes, the maximum page
size is reduced from 2MB to 4KB when -z separate-code is turned on by
default. Note: -z max-page-size= can be used to set the maximum page
size.
> We compared SPEC CPU 2017 performance before and after this change on
Skylake server. There are no any significant performance changes.
Everything is mostly below +/-1%.
Support was also added to LLVMs lld: https://reviews.llvm.org/D64903, however
there is remains off by default.
There were concerns about an increase in binary size, however in our case, the
increase (1 page worth of bytes) would seem negligible, given we are shipping a
multi-megabyte binary, which then downloads 100's of GBs of data.
Also note that most recent versions of distros are shipping a new enough version
of binutils that this is available and/or on by default (assuming the distro has
not turned it off, I haven't checked everywhere):
CentOS 8: 2.30
Debian Buster 2.31.1
Fedora 29: 2.31.1
FreeBSD: 2.33
GNU Guix: 2.33 / 2.34
Ubuntu 18.04: 2.30
Related threads / discussion:
https://bugzilla.redhat.com/show_bug.cgi?id=1623218
While testing #19530 I noticed that we couldn't call dsymutil after LTO:
```bash
../libtool: line 10643: x86_64-apple-darwin16-dsymutil: command not found
```
This updates configure to call `AC_PATH_TOOL` so that we end up with the
full path to dsymutil, similar to `otool` and `install_name_tool`, ie:
`/bitcoin/depends/x86_64-apple-darwin16/share/../native/bin/x86_64-apple-darwin16-otool`.
Debian GCC ignores -Wformat-security, without -Wformat, which
means when we test for it, it currently fails:
```bash
checking whether C++ compiler accepts -Wformat-security... no
...
configure:15907: checking whether C++ compiler accepts -Wformat-security
configure:15926: g++ -std=c++11 -c -g -O2 -Werror -Wformat-security conftest.cpp >&5
cc1plus: error: '-Wformat-security' ignored without '-Wformat' [-Werror=format-security]
cc1plus: all warnings being treated as errors
```
Fix this by just combining the -Wformat and -Wformat-security checks
together.
92bc268e4a build: Detect missed pkg-config early (Hennadii Stepanov)
1739eb23d8 build: Drop unused use_pkgconfig variable (Hennadii Stepanov)
a661449a2e build: Drop use_pkgconfig check for libmultiprocess check (Hennadii Stepanov)
90b95e7929 build: Drop dead non-pkg-config code for libevent check (Hennadii Stepanov)
44a14afbb8 build: Drop dead non-pkg-config code for qrencode check (Hennadii Stepanov)
10cbae0c39 build: Drop dead non-pkg-config code for ZMQ check (Hennadii Stepanov)
06cfc9cadf build: Fix indentation in UNIVALUE check (Hennadii Stepanov)
6fd2118e77 build: Drop dead non-pkg-config code for UNIVALUE check (Hennadii Stepanov)
e9edbe4dbd build: Always use pkg-config (Hennadii Stepanov)
9e2e753b06 build: Always define ZMQ_STATIC for MinGW (Hennadii Stepanov)
Pull request description:
This PR:
- is based on #18297 (already merged)
- drops all of the non-pkg-config paths from the `configure` script
Ref: #17768
ACKs for top commit:
fanquake:
ACK 92bc268e4a. I re-gitian-built. There are a couple follow-ups that I'll PR shortly. Thanks for addressing my feedback above. I took too long to get back to this.
laanwj:
ACK 92bc268e4a
Tree-SHA512: 83c2d9cf03518867a1ebf7e26a8fc5b6dd8962ef983fe0d84e0c7eb74717f4c36a834da02faf0e503ffd87167005351671cf040c0d4ddae57ee152a6ff84012b
c4ffcf07af build: remove BIP70 configure option (fanquake)
Pull request description:
This was left in after #17165, so that anyone who had been compiling
with (already disabled by default) BIP70 would realise that support
had been completely removed in 0.20.0. However we should be able to
remove it for 0.21.0.
ACKs for top commit:
jnewbery:
utACK c4ffcf07af
MarcoFalke:
ACK c4ffcf07af with or without the "catch-all reject"
Tree-SHA512: a5dd4231ed97c9dd1984fb90d69a8725df2fdda0b963269b0575601c74528e5d820a4a863c428f8ede86eaae2a1606671fe1fcebdeb96b1023f7a5f899270284
9952242c03 build: improve builtin_clz* detection (fanquake)
Pull request description:
Fixes#19402.
The way we currently test for `__builtin_clz*` support with `AC_CHECK_DECLS` does not work with Clang:
```bash
configure:21492: clang++-10 -std=c++11 -c -g -O2 -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS conftest.cpp >&5
conftest.cpp💯10: error: builtin functions must be directly called
(void) __builtin_clz;
^
1 error generated.
```
This also removes the `__builtin_clz()` check, as we don't actually use it anywhere, and it's trvial to re-add detection if we do start using it at some point. If this is controversial then I'll add a test for it as well.
ACKs for top commit:
sipa:
ACK 9952242c03
laanwj:
ACK 9952242c03
Tree-SHA512: 695abb1a694a01a25aaa483b4fffa7d598842f2ba4fe8630fbed9ce5450b915c33bf34bb16ad16a16b702dd7c91ebf49fe509a2498b9e28254fe0ec5177bbac0
The way we currently test with AC_CHECK_DECLS do not work with Clang:
```bash
configure:21492: clang++-10 -std=c++11 -c -g -O2 -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS conftest.cpp >&5
conftest.cpp💯10: error: builtin functions must be directly called
(void) __builtin_clz;
^
1 error generated.
```
This also removes the __builtin_clz() check, as we don't actually use
it anywhere, and it's trvial to re-add detection if we do start using
it at some point.
On OS X, when searching Homebrew keg-only packages for BDB 4.8, if we find it,
use BDB_CPPFLAGS and BDB_LIBS instead of CFLAGS and LIBS for the result. This
is (1) more correct, and (2) necessary in order to give this location
priority over other directories in the include search path, which may include
system include directories with other versions of BDB.
fanquake