Description: Partially revert https://chromium.googlesource.com/chromium/src/+/029d4b6 because we're not building from a git checkout, so DownloadPinnedClang() cannot work
Author: Olivier Tilloy <olivier.tilloy@canonical.com>
Forwarded: not-needed

--- a/tools/clang/scripts/build.py
+++ b/tools/clang/scripts/build.py
@@ -718,7 +718,6 @@ def main():
     cc = args.host_cc
     cxx = args.host_cxx
   else:
-    DownloadPinnedClang()
     if sys.platform == 'win32':
       cc = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang-cl.exe')
       cxx = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang-cl.exe')
@@ -729,8 +728,8 @@ def main():
       cxx = cxx.replace('\\', '/')
       lld = lld.replace('\\', '/')
     else:
-      cc = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang')
-      cxx = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang++')
+      cc = os.path.join(args.gcc_toolchain, 'bin', 'gcc')
+      cxx = os.path.join(args.gcc_toolchain, 'bin', 'g++')
 
     if sys.platform.startswith('linux'):
       MaybeDownloadHostGcc(args)
@@ -740,7 +739,7 @@ def main():
     # The host clang has lld, but self-hosting with lld is still slightly
     # broken on mac.
     # TODO: check if this works now.
-    base_cmake_args.append('-DLLVM_ENABLE_LLD=ON')
+    pass
 
   if sys.platform == 'darwin':
     # For libc++, we only want the headers.
@@ -897,6 +896,14 @@ def main():
     else:
       cc = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang')
       cxx = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang++')
+    if sys.platform.startswith('linux'):
+      base_cmake_args.append('-DLLVM_ENABLE_LLD=ON')
+
+    if args.gcc_toolchain:
+      # Tell the bootstrap compiler where to find the standard library headers
+      # and shared object files.
+      cflags.append('--gcc-toolchain=' + args.gcc_toolchain)
+      cxxflags.append('--gcc-toolchain=' + args.gcc_toolchain)
 
     print('Bootstrap compiler installed.')