merge revision(s) f96216df8dfd2d1e206150572912289f4dda7386,0091fac1d8de07e86fef8315ba77609bed9dd7f5,04c704c5c967ea9bded6bf645439fe59c7d9f7d6,23655e6de5ee989feb8c65c7061fe9a71579dc54,7cb8904a12c850ee30dcd67817fa2f9dc3fee813,41168f69fbeb32cfc88210911d62e419b8116589,87f6154bb4c67ca77ee353bb1fe25a922036c0e5: [Backport #17202]

	Remove "All Rights Reserved." from Copyright statement.

	Patch assembly so that it aligns properly

	Removed trailing spaces [ci skip]

	Fix build error on Apple silicon macOS

	This patch will fix following build error on macOS 11.0 + Xcode 12 beta.

	```
	$ ./configure
	$ make V=1
		BASERUBY = /Users/watson/.rbenv/shims/ruby --disable=gems
		CC = clang -fdeclspec
		LD = ld
		LDSHARED = clang -fdeclspec -dynamiclib
		CFLAGS = -O3 -ggdb3 -Wall -Wextra -Werror=deprecated-declarations -Werror=division-by-zero -Werror=implicit-function-declaration -Werror=implicit-int -Werror=misleading-indentation -Werror=pointer-arith -Werror=shorten-64-to-32 -Werror=write-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Werror=extra-tokens -std=gnu99  -pipe
		XCFLAGS = -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fno-strict-overflow -DRUBY_DEVEL=1 -fvisibility=hidden -DRUBY_EXPORT -fPIE -DCANONICALIZATION_FOR_MATHN -I. -I.ext/include/arm64-darwin20 -I./include -I. -I./enc/unicode/12.1.0
		CPPFLAGS = -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT
		DLDFLAGS = -Wl,-undefined,dynamic_lookup -Wl,-multiply_defined,suppress -fstack-protector-strong -Wl,-pie -framework Security -framework Foundation
		SOLIBS = -lpthread -ldl -lobjc
		LANG = ja_JP.UTF-8
		LC_ALL =
		LC_CTYPE =
		MFLAGS =
	Apple clang version 12.0.0 (clang-1200.0.22.19)
	Target: arm64-apple-darwin20.0.0
	Thread model: posix
	InstalledDir: /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
	clang -fdeclspec -O3 -ggdb3 -Wall -Wextra -Werror=deprecated-declarations -Werror=division-by-zero -Werror=implicit-function-declaration -Werror=implicit-int -Werror=misleading-indentation -Werror=pointer-arith -Werror=shorten-64-to-32 -Werror=write-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Werror=extra-tokens -std=gnu99  -pipe  -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fno-strict-overflow -DRUBY_DEVEL=1 -fvisibility=hidden -DRUBY_EXPORT -fPIE -DCANONICALIZATION_FOR_MATHN -I. -I.ext/include/arm64-darwin20 -I./include -I. -I./enc/unicode/12.1.0 -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -o cont.o -c cont.c
	In file included from cont.c:19:
	./coroutine/ucontext/Context.h:32:5: error: 'getcontext' is deprecated: first deprecated in macOS 10.6 [-Werror,-Wdeprecated-declarations]
	    getcontext(&context->state);
	    ^
	/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ucontext.h:37:6: note: 'getcontext' has been
	      explicitly marked deprecated here
	int  getcontext(ucontext_t *) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5, __MAC_10_6, __IPHONE_2_0, __IPHONE_2_0) __WATCHOS_PROHIBITED __TVOS_PROHIBITED;
	     ^
	In file included from cont.c:19:
	./coroutine/ucontext/Context.h:51:5: error: 'makecontext' is deprecated: first deprecated in macOS 10.6 [-Werror,-Wdeprecated-declarations]
	    makecontext(&context->state, (void(*)(void))coroutine_trampoline, 2, (void*)start, (void*)context);
	    ^
	/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ucontext.h:38:6: note: 'makecontext' has been
	      explicitly marked deprecated here
	void makecontext(ucontext_t *, void (*)(), int, ...) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5, __MAC_10_6, __IPHONE_2_0, __IPHONE_2_0) __WATCHOS_PROHI...
	     ^
	In file included from cont.c:19:
	./coroutine/ucontext/Context.h:59:5: error: 'swapcontext' is deprecated: first deprecated in macOS 10.6 [-Werror,-Wdeprecated-declarations]
	    swapcontext(&current->state, &target->state);
	    ^
	/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ucontext.h:40:6: note: 'swapcontext' has been
	      explicitly marked deprecated here
	int  swapcontext(ucontext_t * __restrict, const ucontext_t * __restrict) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5, __MAC_10_6, __IPHONE_2_0, __IPHONE_...
	     ^
	3 errors generated.
	make: *** [cont.o] Error 1
	```

	Extract correct processor name for ARM64 Macs

	Prefix export symbol prefix to coroutine_transfer

	Revert "Revert "[ruby/fiddle] Use ffi_closure_free by default.
	 (#20)""

	This reverts commit efd641ffab34e433a8d8a7d78914576f2425aa90.

	This changeset seems to be needed to suppress a warning on Ubuntu 20.04
	https://rubyci.org/logs/rubyci.s3.amazonaws.com/ubuntu/ruby-master/log/20200304T033004Z.log.html.gz
	```
	closure.c:264:5: warning: 'ffi_prep_closure' is deprecated: use ffi_prep_closure_loc instead [-Wdeprecated-declarations]
	  264 |     result = ffi_prep_closure(pcl, cif, callback, (void *)self);
	      |     ^~~~~~
	```

	I guess there was a reason why the commit was reverted (maybe some CIs
	failed?), so try it again.

2 files changed, 6 insertions, 42 deletions

diff --git a/ext/fiddle/closure.c b/ext/fiddle/closure.c
index 1a80b2b02a..b997e23f45 100644
--- a/ext/fiddle/closure.c
+++ b/ext/fiddle/closure.c
@@ -13,25 +13,11 @@ typedef struct {
     ffi_type **argv;
 } fiddle_closure;
 
-#if defined(USE_FFI_CLOSURE_ALLOC)
-#elif defined(__OpenBSD__) || defined(__APPLE__) || defined(__linux__)
-# define USE_FFI_CLOSURE_ALLOC 0
-#elif defined(RUBY_LIBFFI_MODVERSION) && RUBY_LIBFFI_MODVERSION < 3000005 && \
-	(defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || defined(_M_AMD64))
-# define USE_FFI_CLOSURE_ALLOC 0
-#else
-# define USE_FFI_CLOSURE_ALLOC 1
-#endif
-
 static void
 dealloc(void * ptr)
 {
     fiddle_closure * cls = (fiddle_closure *)ptr;
-#if USE_FFI_CLOSURE_ALLOC
     ffi_closure_free(cls->pcl);
-#else
-    munmap(cls->pcl, sizeof(*cls->pcl));
-#endif
     if (cls->argv) xfree(cls->argv);
     xfree(cls);
 }
@@ -205,12 +191,7 @@ allocate(VALUE klass)
     VALUE i = TypedData_Make_Struct(klass, fiddle_closure,
 	    &closure_data_type, closure);
 
-#if USE_FFI_CLOSURE_ALLOC
     closure->pcl = ffi_closure_alloc(sizeof(ffi_closure), &closure->code);
-#else
-    closure->pcl = mmap(NULL, sizeof(ffi_closure), PROT_READ | PROT_WRITE,
-        MAP_ANON | MAP_PRIVATE, -1, 0);
-#endif
 
     return i;
 }
@@ -257,17 +238,8 @@ initialize(int rbargc, VALUE argv[], VALUE self)
     if (FFI_OK != result)
 	rb_raise(rb_eRuntimeError, "error prepping CIF %d", result);
 
-#if USE_FFI_CLOSURE_ALLOC
     result = ffi_prep_closure_loc(pcl, cif, callback,
 		(void *)self, cl->code);
-#else
-    result = ffi_prep_closure(pcl, cif, callback, (void *)self);
-    cl->code = (void *)pcl;
-    i = mprotect(pcl, sizeof(*pcl), PROT_READ | PROT_EXEC);
-    if (i) {
-	rb_sys_fail("mprotect");
-    }
-#endif
 
     if (FFI_OK != result)
 	rb_raise(rb_eRuntimeError, "error prepping closure %d", result);
diff --git a/ext/fiddle/extconf.rb b/ext/fiddle/extconf.rb
index fce0cb4079..5525b2c808 100644
--- a/ext/fiddle/extconf.rb
+++ b/ext/fiddle/extconf.rb
@@ -7,8 +7,7 @@ bundle = enable_config('bundled-libffi')
 if ! bundle
   dir_config 'libffi'
 
-  pkg_config("libffi") and
-    ver = pkg_config("libffi", "modversion")
+  pkg_config("libffi")
 
   if have_header(ffi_header = 'ffi.h')
     true
@@ -28,20 +27,20 @@ begin
     Dir.glob("#{$srcdir}/libffi-*/").each{|dir| FileUtils.rm_rf(dir)}
     extlibs.run(["--cache=#{cache_dir}", ext_dir])
   end
-  ver = bundle != false &&
+  libffi_dir = bundle != false &&
         Dir.glob("#{$srcdir}/libffi-*/")
         .map {|n| File.basename(n)}
         .max_by {|n| n.scan(/\d+/).map(&:to_i)}
-  unless ver
+  unless libffi_dir
     raise "missing libffi. Please install libffi."
   end
 
-  srcdir = "#{$srcdir}/#{ver}"
+  srcdir = "#{$srcdir}/#{libffi_dir}"
   ffi_header = 'ffi.h'
   libffi = Struct.new(*%I[dir srcdir builddir include lib a cflags ldflags opt arch]).new
-  libffi.dir = ver
+  libffi.dir = libffi_dir
   if $srcdir == "."
-    libffi.builddir = "#{ver}/#{RUBY_PLATFORM}"
+    libffi.builddir = "#{libffi_dir}/#{RUBY_PLATFORM}"
     libffi.srcdir = "."
   else
     libffi.builddir = libffi.dir
@@ -52,7 +51,6 @@ begin
   libffi.a = "#{libffi.lib}/libffi_convenience.#{$LIBEXT}"
   nowarn = CONFIG.merge("warnflags"=>"")
   libffi.cflags = RbConfig.expand("$(CFLAGS)".dup, nowarn)
-  ver = ver[/libffi-(.*)/, 1]
 
   FileUtils.mkdir_p(libffi.dir)
   libffi.opt = CONFIG['configure_args'][/'(-C)'/, 1]
@@ -112,12 +110,6 @@ begin
   $INCFLAGS << " -I" << libffi.include
 end
 
-if ver
-  ver = ver.gsub(/-rc\d+/, '') # If ver contains rc version, just ignored.
-  ver = (ver.split('.') + [0,0])[0,3]
-  $defs.push(%{-DRUBY_LIBFFI_MODVERSION=#{ '%d%03d%03d' % ver }})
-end
-
 have_header 'sys/mman.h'
 
 if have_header "dlfcn.h"