sys-libs/musl: create relative symlink to libc.so if existing one fails

The build system seems to create an absolute symlink to libc.so on
the host which may not exist.

If it doesn't (to avoid being disruptive, we could do this unconditionally),
create a new one relative within ${D} to facilitate SYSROOT installs.

I've hit this a few times when using crossdev but finally dug into it
a bit more.

Bug: https://bugs.gentoo.org/732482
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 18 insertions, 2 deletions

diff --git a/sys-libs/musl/musl-9999.ebuild b/sys-libs/musl/musl-9999.ebuild
index 56a2bbbc42f6..5736eadc0fb4 100644
--- a/sys-libs/musl/musl-9999.ebuild
+++ b/sys-libs/musl/musl-9999.ebuild
@@ -3,7 +3,7 @@
 
 EAPI=7
 
-inherit flag-o-matic toolchain-funcs
+inherit eapi8-dosym flag-o-matic toolchain-funcs
 if [[ ${PV} == "9999" ]] ; then
 	EGIT_REPO_URI="git://git.musl-libc.org/musl"
 	inherit git-r3
@@ -120,7 +120,23 @@ src_install() {
 		#   SUBARCH = ...
 		# and print $(ARCH)$(SUBARCH).
 		local arch=$(awk '{ k[$1] = $3 } END { printf("%s%s", k["ARCH"], k["SUBARCH"]); }' config.mak)
-		[[ -e "${D}"/lib/ld-musl-${arch}.so.1 ]] || die
+
+		if [[ ! -e "${D}"/lib/ld-musl-${arch}.so.1 ]] ; then
+			# During cross (using crossdev), when emerging sys-libs/musl,
+			# if /usr/lib/libc.so.1 doesn't exist on the system, installation
+			# would fail.
+			#
+			# The musl build system seems to create a symlink:
+			# ${D}/lib/ld-musl-${arch}.so.1 -> /usr/lib/libc.so.1 (absolute)
+			# During cross, there's no guarantee that the host is using musl
+			# so that file may not exist. Use a relative symlink within ${D}
+			# instead.
+			dosym8 -r /usr/lib/libc.so.1 /lib/ld-musl-${arch}.so.1
+
+			# If it's still a dead symlnk, OK, we really do need to abort.
+			[[ -e "${D}"/lib/ld-musl-${arch}.so.1 ]] || die
+		fi
+
 		cp "${FILESDIR}"/ldconfig.in "${T}" || die
 		sed -e "s|@@ARCH@@|${arch}|" "${T}"/ldconfig.in > "${T}"/ldconfig || die
 		into /