buildMozillaMach: Add RELRHACK_LINKER patch (#401323)

From 45d40b3eeb393051bd3a49feebcefe39dc6e4e93 Mon Sep 17 00:00:00 2001

From: Peter Collingbourne <pcc@google.com>

Date: Wed, 23 Apr 2025 21:13:38 -0700

Subject: [PATCH] build: fix RELRHACK_LINKER setting when linker name is target

 triple prefixed

RELRHACK_LINKER is used as the name of a binary installed in a

directory specified with -B to override the linker. Both Clang and

GCC will only look for a binary named "ld" (or "ld.$fuse_ld_setting"

if -fuse-ld= is specified) in the -B directories, which means that

if the linker name does not follow this pattern, for example if it

is named $target_triple-ld", the relrhack linker will not be found,

the compiler will use the normal linker and the link will fail. To fix

this problem, use the correct pattern to name the relrhack executable.

---

 toolkit/moz.configure | 16 ++++++++--------

 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/toolkit/moz.configure b/toolkit/moz.configure

index 6c47287a5b..1a9c368e5e 100644

--- a/toolkit/moz.configure

+++ b/toolkit/moz.configure

@@ -1843,23 +1843,23 @@ with only_when("--enable-compile-environment"):

     use_relrhack = depends(which_elf_hack)(lambda x: x == "relr")

     set_config("RELRHACK", True, when=use_relrhack)

-    @depends(c_compiler, linker_ldflags, when=use_relrhack)

-    def relrhack_real_linker(c_compiler, linker_ldflags):

+    @depends(linker_ldflags, when=use_relrhack)

+    def relrhack_linker(linker_ldflags):

         ld = "ld"

         for flag in linker_ldflags:

             if flag.startswith("-fuse-ld="):

                 ld = "ld." + flag[len("-fuse-ld=") :]

+        return ld

+

+    set_config("RELRHACK_LINKER", relrhack_linker)

+

+    @depends(c_compiler, relrhack_linker, when=use_relrhack)

+    def relrhack_real_linker(c_compiler, ld):

         ld = check_cmd_output(

             c_compiler.compiler, f"--print-prog-name={ld}", *c_compiler.flags

         )

         return ld.rstrip()

-    @depends(relrhack_real_linker, when=use_relrhack)

-    def relrhack_linker(ld):

-        return os.path.basename(ld)

-

-    set_config("RELRHACK_LINKER", relrhack_linker)

-

     std_filesystem = host_cxx_compiler.try_run(

         header="#include <filesystem>",

         body='auto foo = std::filesystem::absolute("");',

-- 

2.49.0.805.g082f7c87e0-goog

      # Fix for missing vector header on macOS

      # https://bugzilla.mozilla.org/show_bug.cgi?id=1939405

      ./firefox-mac-missing-vector-header.patch

      # https://bugzilla.mozilla.org/show_bug.cgi?id=1962497

      # https://phabricator.services.mozilla.com/D246545

      ./build-fix-RELRHACK_LINKER-setting-when-linker-name-i.patch

    ]

    ++ extraPatches;