multilib.eclass: multilib_env(): set LIBDIR=lib for *-musl*

In contrast to glibc musl profiles use 'lib' layour for 32-bit
and 64-bit targets. multilib_env() did not take it into account
and assumed glibc's lib64 layout.

That breaks crossdev as it uses multilib_env to extract target
definition. Native builds are unaffected by this change.

Bug: https://bugs.gentoo.org/675954
Bug: https://gcc.gnu.org/PR90077
Bug: gentoo/musl#245
Signed-off-by: Sergei Trofimovich <[email protected]>

Author: Sergei Trofimovich

eclass/multilib.eclass

@@ -294,11 +294,22 @@ get_modname() {
 }
 
 # This is for the toolchain to setup profile variables when pulling in
-# a crosscompiler (and thus they aren't set in the profile)
+# a crosscompiler (and thus they aren't set in the profile).
 multilib_env() {
 	local CTARGET=${1:-${CTARGET}}
 	local cpu=${CTARGET%%*-}
 
+	if [[ ${CTARGET} = *-musl* ]]; then
+		# musl has no multilib support and can run only in 'lib':
+		# - https://bugs.gentoo.org/675954
+		# - https://gcc.gnu.org/PR90077
+		# - https://github.com/gentoo/musl/issues/245
+		: ${MULTILIB_ABIS=default}
+		: ${DEFAULT_ABI=default}
+		export MULTILIB_ABIS DEFAULT_ABI
+		return
+	fi
+
 	case ${cpu} in
 		aarch64*)
 			# Not possible to do multilib with aarch64 and a single toolchain.

eclass/tests/multilib.sh

@@ -57,5 +57,9 @@ test-multilib_env \
 	"x86_64-pc-linux-gnux32" \
 	"x32:x32 amd64 x86" \
 	"x32? ( CHOST=x86_64-pc-linux-gnux32 LIBDIR=libx32 CFLAGS=-mx32 LDFLAGS= ) amd64? ( CHOST=x86_64-pc-linux-gnu LIBDIR=lib64 CFLAGS=-m64 LDFLAGS= ) x86? ( CHOST=i686-pc-linux-gnu LIBDIR=lib CFLAGS=-m32 LDFLAGS= )"
+test-multilib_env \
+	"x86_64-gentoo-linux-musl" \
+	"default:default" \
+	"default? ( CHOST=x86_64-gentoo-linux-musl LIBDIR=lib CFLAGS= LDFLAGS= )"
 
 texit