Revert "Revert "Revert "[ruby/fiddle] Use ffi_closure_free by
default. (#20)"""
This reverts commit 87f6154bb4.
It turned out that the change fails to build on macOS
https://rubyci.org/logs/rubyci.s3.amazonaws.com/osx1014/ruby-master/log/20200304T074503Z.fail.html.gz
```
+ make 'TESTS=--hide-skip -v fiddle' RUBYOPT=-w test-all
dyld: lazy symbol binding failed: Symbol not found: _ffi_closure_alloc
Referenced from: /Users/hsbt/Documents/cb/tmp/build/20200304T074503Z/ruby/.ext/x86_64-darwin18/fiddle.bundle
Expected in: flat namespace
dyld: Symbol not found: _ffi_closure_alloc
Referenced from: /Users/hsbt/Documents/cb/tmp/build/20200304T074503Z/ruby/.ext/x86_64-darwin18/fiddle.bundle
Expected in: flat namespace
make: *** [yes-test-all] Abort trap: 6
```
[ruby/fiddle] Use ffi_closure_free if available
[ruby/fiddle] ffi_closure_free is available in the bundled libffi
[ruby/fiddle] use ffi_closure_alloc only with 3.2 or later
[ruby/fiddle] always use ffi_closure_alloc on Windows
Fixed a typo
Show libffi version only if set
ext/fiddle/extconf.rb: check if ffi_closure_alloc is available
to define HAVE_FFI_CLOSURE_ALLOC.
The macro is used in closure.c, so have_func check is needed.
If pkg-config is not installed, extconf.rb fails to detect the version
of libffi, and does not add "-DUSE_FFI_CLOSURE_ALLOC=1" even when system
libffi version is >= 3.2.
If USE_FFI_CLOSURE_ALLOC is not defined, closure.c attempts to check if
HAVE_FFI_CLOSURE_ALLOC is defined or not, but have_func was removed with
528a3a1797, so the macro is always not
defined.
This resulted in this deprecation warning:
https://rubyci.org/logs/rubyci.s3.amazonaws.com/ubuntu2004/ruby-master/log/20200512T123003Z.log.html.gz
```
compiling closure.c
closure.c: In function 'initialize':
closure.c:265:5: warning: 'ffi_prep_closure' is deprecated: use ffi_prep_closure_loc instead [-Wdeprecated-declarations]
265 | result = ffi_prep_closure(pcl, cif, callback, (void *)self);
| ^~~~~~
In file included from ./fiddle.h:42,
from closure.c:1:
/usr/include/x86_64-linux-gnu/ffi.h:334:1: note: declared here
334 | ffi_prep_closure (ffi_closure*,
| ^~~~~~~~~~~~~~~~
```
Do not try ffi_closure_alloc if libffi is <= 3.1
Maybe due to e1855100e4, CentOS, RHEL, and
Fedora CIs have started failing with SEGV. Try to avoid
ffi_closure_alloc on those environments.
https://rubyci.org/logs/rubyci.s3.amazonaws.com/centos8/ruby-master/log/20200512T183004Z.fail.html.gzhttps://rubyci.org/logs/rubyci.s3.amazonaws.com/fedora32/ruby-master/log/20200512T183004Z.fail.html.gzhttps://rubyci.org/logs/rubyci.s3.amazonaws.com/rhel8/ruby-master/log/20200512T183003Z.fail.html.gz
ext/fiddle/extconf.rb: Fix the condition of libffi <= 3.1
ver is [3, 1, 0] which is not less then or equal to [3, 1]
229c041f05