Readjust the old pkg_setup logic for BROOT tool use, move it to llvm_cbuild_setup function.

Signed-off-by: Michał Górny <mgorny@gentoo.org>
---
eclass/llvm-r2.eclass | 45 ++++++++++++++++++++++++++++++++-----------
1 file changed, 34 insertions(+), 11 deletions(-)

diff --git a/eclass/llvm-r2.eclass b/eclass/llvm-r2.eclass
index 6d0223f73f10..93c16e75be83 100644
--- a/eclass/llvm-r2.eclass
+++ b/eclass/llvm-r2.eclass
@@ -216,6 +216,38 @@ get_llvm_prefix() {
echo "${prefix}/usr/lib/llvm/${LLVM_SLOT}"
}

+# @FUNCTION: llvm_cbuild_setup
+# @DESCRIPTION:
+# Prepend the PATH for selected LLVM version in CBUILD.
+#
+# This function is meant to be used when the package in question uses
+# LLVM tools at build time. It is called automatically
+# by llvm-r2_pkg_setup if LLVM is found installed in BROOT.
+#
+# Note that llvm-config from this path must not be used to build against
+# LLVM, as that will break cross-compilation.
+llvm_cbuild_setup() {
+ debug-print-function ${FUNCNAME} "$@"
+
+ local broot_prefix=$(get_llvm_prefix -b)
+ einfo "Using ${broot_prefix} for CBUILD LLVM ${LLVM_SLOT}"
+ [[ -d ${broot_prefix}/bin ]] ||