The warning against `-undefined dynamic_lookup` is just a warning yet,
and many gems seem to pay no attention to warnings. Until it fails
actually, keep it as a migration path, except for standard extension
libraries and bundled extension gems.
For the macOS -bundle_loader linker option, we need a path to the
Ruby exectuable. $(RUBY) is not necessarily a path since it could
be a command line invocation. That happens during build with
runruby.rb and can happen post installation if the user passes
the --ruby option to a extconf.rb. Use $(bindir) to locate
the executable instead.
Before installation, $(bindir) doesn't exist, so we need to be
able to override $(BUILTRUBY) in such situations so test-spec
and bundled extensions could build. Use a new mkmf global,
$builtruby, to do this; set it in fake.rb and in extmk.rb.
Our build system is quite complex...
ld64 shipped with Xcode 14 emits a warning when using `-undefined
dynamic_lookup`.
```
ld: warning: -undefined dynamic_lookup may not work with chained fixups
```
Actually, `-undefined dynamic_lookup` doesn't work when:
1. Link a *shared library* with the option
2. Link it with a program that uses the chained-fixup introduced from
macOS 12 and iOS 15
because `-undefined dynamic_lookup` uses lazy-bindings and they won't be
bound while dyld fixes-up by traversing chained-fixup info.
However, we build exts as *bundles* and they are loaded only through
`dlopen`, so it's safe to use `-undefined dynamic_lookup` in theory.
So the warning produced by ld64 is false-positive, and it results
failure of option checking in configuration. Therefore, it would be an
option to ignore the warning during our configuration.
On the other hand, `-undefined dynamic_lookup` is already deprecated on
all darwin platforms except for macOS, so it's good time to get rid of
the option. ld64 also provides `-bundle_loader <executable>` option,
which allows to resolve symbols defined in the executable symtab while
linking. It behaves almost the same with `-undefined dynamic_lookup`,
but it makes the following changes:
1. Require that unresolved symbols among input objects must be defined
in the executable.
2. Lazy symbol binding will lookup only the symtab of the bundle loader
executable. (`-undefined dynamic_lookup` lookups all symtab as flat
namespace)
This patch adds `-bundle_loader $(RUBY)` when non-EXTSTATIC
configuration by assuming ruby executable can be linked before building
exts.
See "New Features" subsection under "Linking" section for chained fixup
https://developer.apple.com/documentation/xcode-release-notes/xcode-13-release-notes
Note this change is only for `configure.ac`, not for Windows using
`win32/configure.bat`.
```
$ ./configure --help | grep mkmf
--enable-mkmf-verbose enable verbose in mkmf
```
Run the following command to enable the mkmf verbose mode.
```
$ ./configure --enable-mkmf-verbose
$ grep MKMF_VERBOSE config.status
S["MKMF_VERBOSE"]="1"
```
In this mkmf verbose mode, when compiling a native extension, the
`rake compile` prints the compiling commands such as
"gcc -I. <...> path/to/file" instead of "compiling path/to/file".
```
$ git clone https://github.com/deivid-rodriguez/byebug.git
$ cd byebug
$ bundle install --standalone
$ bundle exec rake compile
...
gcc -I. <...> path/to/file
...
```
This method is at least 7 years old and is widely used in the wild.
Since we need to support it, let's document it to make it discoverable.
Add docs and move it out of the `# :stopdoc:` zone.
When installing an extension library which provides a header, that
header should be installed under site_ruby (or vendor_ruby when
"--vendor" option was given to extconf.rb). However, currently
this file is about to be installed in the core include directory.
iff means if and only if, but readers without that knowledge might
assume this to be a spelling mistake. To me, this seems like
exclusionary language that is unnecessary. Simply using "if and only if"
instead should suffice.
Look up language module with `MakeMakefile.[]`, insted of a
accessing constant under that module directly, to get rid of
expose the constant to the toplevel inadvertently.
This was the historical behavior, it was modified unintentionally
by 097c3e9cbb, which started storing
these flags in a different global variable.
Also, include the incflags when logging, and document that the
method modifies $INCFLAGS.
Fixes [Bug #10651]
Nobuyoshi Nakada
Alan Wu
Yuta Saito
Jun Aruga
Kaíque Kandy Koga
Kazuhiro NISHIYAMA
Mike Dalessio
Gannon McGibbon
Jeremy Evans