cmake{,-devel}: fix build before 10.10

[catap]

Description

cmake is required to build all clangs, and to prevent dependency loop I've used clang-11-bootstrap to build it on platforms which can't build it by compiler which is ships with it.

Closes: https://trac.macports.org/ticket/66340
Closes: https://trac.macports.org/ticket/66040

I've also made port lint --nitpick cmake-devel happy.

Type(s)

• bugfix

Tested on

macOS 10.7.5 11G63 x86_64
Xcode 4.6.3 4H1503

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL?
• checked your Portfile with port lint --nitpick?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?

[macportsbot]

Notifying maintainers:
@mascguy for port cmake-devel.
@michaelld for port cmake-devel, cmake.

[catap]

@michaelld to be clear about fix: cmake is used to build clang-15 for example, and without cmake it is impossible to build clang-15.

Here we have chicken and the egg issue, and clang-11-bootstrap (and gcc10-bootstrap) was made special to broke such dependency cycles and solve such issue.

[michaelld]

Good start & I totally agree that not all compilers that claim to support C++11 actually do support it. My inclination is to bump the required compiler to C++14 or even C++17, as those are available on all platforms and macOS / OSX versions these days, and should supersede the C++11 issue. I don't have an OSX 10.7/8/9 box up and running, so I can't test this. Hoping others can comment on this overall issue.

[michaelld]

why remove platform darwin & move to this if clause? I think they do the same thing, and I prefer the current version

[catap]

@michaelld am I right that you would like to have?

platform darwin {
    if {${os.major} < 14 && ${build_arch} ni [list ppc ppc64]} {
        configure.compiler.add_deps no

        depends_build-append   port:clang-11-bootstrap
        depends_skip_archcheck-append \
            clang-11-bootstrap

        configure.cc           ${prefix}/libexec/clang-11-bootstrap/bin/clang
        configure.cxx          ${prefix}/libexec/clang-11-bootstrap/bin/clang++

        configure.cxx_stdlib   libc++
        depends_lib-append     port:libcxx
    }
}

I haven't done that to keep code flatten, but I can rollback to this style.

[michaelld]

Thinking the clause ${build_arch} ni [list ppc ppc64] can be removed, yes? PPC/64 needs to be handled here, as it was before. I don't have a PPC/64 box running at the moment, so maybe @kencu can comment on this?

[catap]

clang-11-bootstrap aren't available on ppc :) because PPC hasn't got clang.

So, this condition is mandatory. I may reverse it to ${build_arch} in [list i386 x86_64] if you would like.

[michaelld]

Is this extra space to make lint happy? Prefer to not have it, regardless of what lint says ...

[catap]

@michaelld yeah, it does. Without it lint complains like:

Warning: Line 10 should be a newline (after PortGroup)

BTW, cmake port has the same empty line. I assume by the same reason :)

[catap]

@michaelld the issue with the way to simple bump that clang which can build it requires cmake to be built :(

[catap]

Let me rephrase it.

MacPorts contains a lot of clang, for example clang-15 which can build cmake without any issue.

But, here, the catch: clang-15 depends on cmake.

Frankly speaking the only clang which doesn't depends on this port is clang-11-bootstrap. It depends on cmake-bootstrap which can be build without libc++.

It was made to bootstrap libcxx. Now, it seems, that we need this compiler to bootstrap cmake which is required to bootstrap all another clangs.

[catap]

@michaelld right now all ports which is used cmake aren't build by buildbots before 10.10 because of broken cmake.

May I ask you to move forward with this fix?

Frankly speaking I doubt that any another way to fix it possible.

[catap]

@ryandesign , @kencu, @jmroot what do you think about this PR?

[jmroot]

Just bumping the cxx_standard to 2014 should have the desired effect of excluding the system clang on 10.9 and older. The clang_dependency portgroup already takes care of the circular dependency problems. The one problem is Lion, where cmake currently forces clang-3.4, which doesn't work. Apparently this is because 3.4 has a fix for a Lion-specific libc++ bug which 3.7 (at least) doesn't have. It seems like we should bring that fix forward into all the clangs that don't have it.

[catap]

@jmroot why not use clang-11-bootstrap instead which is used to build libcxx?

[jmroot]

No need apparently; I just tried it and clang-3.7 built cmake OK on 10.7. I guess something changed in the 5 years since that workaround was added.

So the change needed is:

--- a/devel/cmake/Portfile
+++ b/devel/cmake/Portfile
@@ -41,7 +41,7 @@ checksums           rmd160  09373f97fee569133852498f0de6e9f6db10084b \
 revision            0
 
 gitlab.livecheck.regex {([0-9.]+)}
-compiler.cxx_standard 2011
+compiler.cxx_standard 2014
 
 platform darwin {
     if {!((${os.major} < 9) || ${build_arch} eq "ppc" ||
@@ -102,14 +102,6 @@ if {${os.platform} eq "darwin" && ${os.major} <= 10 &&
     set cmake_bootstrapping yes
 }
 
-# On Lion, Clang 3.3 produces bad stream reading code when using
-# libc++.  See https://trac.macports.org/ticket/44129 . Clang 3.4
-# works. But Clang 3.7 doesn't work.
-if {${os.platform} eq "darwin" && ${os.major} == 11 &&
-    ${configure.cxx_stdlib} eq "libc++"} {
-    compiler.whitelist macports-clang-3.4
-}
-
 # clang 3.4 can't build certain parts of the
 # cmake self-testing infrastructure
 # https://trac.macports.org/ticket/59782

[catap]

@jmroot indeed, your way is cleaner 🤦

Pushed better version. Thanks.

[michaelld]

LGTM ; thx!