chromium: Fix incremental build error after meta-clang update (#814)

Fixes #794.

Build and patch changes:
------------------------

We previously created a symlink pointing to the subdirectory of the
latest version under $STAGING_LIBDIR_NATIVE/clang, and then copied the
libclang_rt.builtins library from $STAGING_LIBDIR/clang to the same
directory as the native library. This is necessary because we need to
point Chromium to a single clang directory for building both native and
target code, and we need its path to be independent of the specific
clang version used.

However, the chosen approach leads to an error when doing a build,
updating meta-clang to a revision containing a new version of clang, and
then doing an incremental build.

This commit replaces the previous approach with a more safe one that
does a full copy of the $STAGING_LIBDIR_NATIVE/clang subdirectory that
we want to point Chromium to, and then copies the libclang_rt.builtins
library for the target architecture to this copied directory.

License changes:
----------------

Added licenses: none.

Removed licenses: none.

Updated licenses: none.

Test-built:
-----------

* chromium-x11:
 - master, clang, MACHINE=qemuarm64

Signed-off-by: Max Ihlenfeldt <[email protected]>

Author: MaxIhlenfeldt

meta-chromium/recipes-browser/chromium/chromium-gn.inc

@@ -289,8 +289,8 @@ GN_ARGS += ' \
 '
 
 # Make sure Chromium is able to find clang libraries. See
-# 0023-Use-the-correct-path-to-libclang_rt.builtins.a.patch and the
-# add_clang_symlink and copy_clang_library tasks for more context.
+# 0008-Use-the-correct-path-to-libclang_rt.builtins.a.patch and the
+# add_clang_latest and copy_clang_library tasks for more context.
 GN_ARGS += ' \
         clang_base_path="${@clang_install_path(d)}" \
         clang_version="latest" \
@@ -436,33 +436,36 @@ do_add_nodejs_symlink () {
 }
 addtask add_nodejs_symlink after do_configure before do_compile
 
-do_add_clang_symlink () {
-    # Creates a `latest` symlink in the native sysroot's /usr/lib/clang
-    # directory that points to /usr/lib/clang/$CLANG_VERSION. Chromium manually
-    # links against libclang_rt.builtins.a and uses the `clang_version` GN
-    # variable to find it. This allows us to set it to the same value for all
+do_add_clang_latest () {
+    # Creates a `latest` directory in the native sysroot's /usr/lib/clang
+    # directory that is a copy of /usr/lib/clang/$CLANG_VERSION. Chromium
+    # manually links against libclang_rt.builtins.a and uses the `clang_version`
+    # GN variable to find it. This allows us to set it to the same value for all
     # Yocto releases.
     cd "${STAGING_LIBDIR_NATIVE}/clang"
+    rm -rf latest
     # find the directory containing the library
     for dir in *; do
         if [ -n "$(find $dir -name 'libclang_rt.builtins*')" ] ; then
-            ln -sf "$dir" latest
+            cp -r "$dir" latest
             break
         fi
     done
 }
-addtask add_clang_symlink after do_configure before do_compile
+addtask add_clang_latest after do_configure before do_compile
 
 do_copy_clang_library () {
     # Chromium needs to link against libclang_rt.builtins.a for both host and
     # target code, and expects to find both libraries in the same directory
-    # (thanks to 0023-Use-the-correct-path-to-libclang_rt.builtins.a.patch).
-    cd "${STAGING_LIBDIR}"
-    lib_file="$(find clang -name 'libclang_rt.builtins*')"
-    lib_dir="$(dirname $lib_file)"
-    cp "$lib_file" "${STAGING_LIBDIR_NATIVE}/$lib_dir"
+    # (thanks to 0008-Use-the-correct-path-to-libclang_rt.builtins.a.patch).
+    cd "${STAGING_LIBDIR}/clang"
+    # lib_file = "./$CLANG_VERSION/lib/linux/libclang_rt.builtins-$ARCH.a"
+    lib_file="$(find . -name 'libclang_rt.builtins*')"
+    # stripped_lib_file = "lib/linux/libclang_rt.builtins-$ARCH.a"
+    stripped_lib_file="${lib_file#*/*/}"
+    cp "$lib_file" "${STAGING_LIBDIR_NATIVE}/clang/latest/${stripped_lib_file}"
 }
-addtask copy_clang_library after do_configure before do_compile
+addtask copy_clang_library after do_add_clang_latest before do_compile
 
 do_copy_target_rustlibs () {
     # Chromium needs a single Rust sysroot that contains the rustlibs for both