WIP

Library/Homebrew/extend/ENV/super.rb

@@ -306,6 +306,7 @@ def determine_optflags
     odebug "Building a bottle for custom architecture (#{effective_arch})..."
     Hardware::CPU.arch_flag(effective_arch)
   end
+  alias generic_determine_optflags determine_optflags
 
   sig { returns(String) }
   def determine_cccfg

Library/Homebrew/extend/os/linux/extend/ENV/super.rb

@@ -45,15 +45,29 @@ def homebrew_extra_paths
 
   def homebrew_extra_isystem_paths
     paths = []
-    # Add paths for GCC headers when building against [email protected] because we have to use -nostdinc.
-    if deps.any? { |d| d.name == "[email protected]" }
+    # Add paths for GCC headers when building against [email protected] or [email protected]
+    # because we have to use -nostdinc.
+    if deps.any? { |d| d.name == "[email protected]" || d.name == "[email protected]" }
       gcc_include_dir = Utils.safe_popen_read(cc, "--print-file-name=include").chomp
       gcc_include_fixed_dir = Utils.safe_popen_read(cc, "--print-file-name=include-fixed").chomp
       paths << gcc_include_dir << gcc_include_fixed_dir
     end
     paths
   end
 
+  sig { returns(String) }
+  def determine_optflags
+    if effective_arch == :armv8 &&
+       compiler.match?(GNU_GCC_REGEXP) &&
+       DevelopmentTools.gcc_version(compiler.to_s) >= "9.3.1"
+      # Out-of-line atomics are not supported out-of-the-box on all systems.
+      # https://learn.arm.com/learning-paths/servers-and-cloud-computing/lse/intro/
+      "#{generic_determine_optflags} -mno-outline-atomics"
+    else
+      generic_determine_optflags
+    end
+  end
+
   def determine_rpath_paths(formula)
     PATH.new(
       *formula&.lib,

Library/Homebrew/shims/super/cc

@@ -313,8 +313,9 @@ class Cmd
   def cppflags
     args = []
     args += path_flags("-isystem", isystem_paths) + path_flags("-I", include_paths)
-    # Add -nostdinc when building against [email protected] to avoid mixing system and brewed glibc headers.
-    args << "-nostdinc" if @deps.include?("[email protected]")
+    # Add -nostdinc when building against [email protected] or [email protected] to avoid
+    # mixing system and brewed glibc headers.
+    args << "-nostdinc" if (@deps & ["[email protected]", "[email protected]"]).any?
     # Ideally this would be -ffile-prefix-map, but that requires a minimum of GCC 8, LLVM Clang 10 or Apple Clang 12
     # and detecting the version dynamically based on what `HOMEBREW_CC` may have been rewritten to point to is awkward
     args << "-fdebug-prefix-map=#{formula_buildpath}=." if formula_buildpath && !debug_symbols?
@@ -340,19 +341,20 @@ class Cmd
   end
 
   def ldflags_linux(args)
+    versioned_glibc_dep = (@deps & ["[email protected]", "[email protected]"]).first
     unless mode == :ld
       wl = "-Wl,"
-      if @deps.include?("[email protected]")
-        args << "-B#{@opt}/[email protected]/lib"
+      if versioned_glibc_dep
+        args << "-B#{@opt}/#{versioned_glibc_dep}/lib"
       else
         args << "-B#{@opt}/glibc/lib"
       end
     end
     args += rpath_flags("#{wl}-rpath=", rpath_paths)
     args += ["#{wl}--dynamic-linker=#{dynamic_linker_path}"] if dynamic_linker_path
-    # Use -rpath-link to make sure linker uses [email protected] rather than the system glibc for indirect
+    # Use -rpath-link to make sure linker uses [email protected] or [email protected] rather than the system glibc for indirect
     # dependencies because -L will only handle direct dependencies.
-    args << "#{wl}-rpath-link=#{@opt}/[email protected]/lib" if @deps.include?("[email protected]")
+    args << "#{wl}-rpath-link=#{@opt}/#{versioned_glibc_dep}/lib" if versioned_glibc_dep
     args
   end