[openwrt/openwrt] scripts: bundle-libraries.sh: fix broken SDK compiler

[LEDE Commits]

jow pushed a commit to openwrt/openwrt.git, branch openwrt-19.07:
https://git.openwrt.org/dce6b118eb9f9c43f93de3a4570d5b36f731e62e

commit dce6b118eb9f9c43f93de3a4570d5b36f731e62e
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Sun Nov 1 14:40:02 2020 +0100

    scripts: bundle-libraries.sh: fix broken SDK compiler
    
    Recent versions (> 5.33) of `file` report liblto_plugin.so as
    executable:
    
     $ file liblto_plugin.so
     liblto_plugin.so.0.0.0: ELF 64-bit LSB pie executable ...
    
    Which then leads to improper packaging of the plugin, resulting in the
    broken compiler:
    
     configure: checking whether the C compiler works
     mips-openwrt-linux-musl/bin/ld: liblto_plugin.so: error loading plugin: liblto_plugin.so: invalid ELF header
    
    As the LTO compiler plugin library is incorrectly packaged as SDK
    executable:
    
     $ head -1 ~/staging_dir/toolchain...libexec/gcc/.../liblto_plugin.so
     #!/usr/bin/env bash
    
    Fix this by filtering out shared libraries from the patching.
    
    Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1296868
    Acked-by: Jo-Philipp Wich <jo at mein.io>
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
    (cherry picked from commit 4b7165722cb0e2ba62ab68e8b90d4d4b0909744c)
---
 scripts/bundle-libraries.sh | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/scripts/bundle-libraries.sh b/scripts/bundle-libraries.sh
index d3c7206a4d..90002453ec 100755
--- a/scripts/bundle-libraries.sh
+++ b/scripts/bundle-libraries.sh
@@ -125,6 +125,23 @@ _patch_glibc() {
 	fi
 }
 
+should_be_patched() {
+	local bin="$1"
+
+	[ -x "$bin" ] || return 1
+
+	case "$bin" in
+		*.so|*.so.[0-9]*)
+			return 1
+		;;
+		*)
+			file "$bin" | grep -sqE "ELF.*(executable|interpreter)" && return 0
+		;;
+	esac
+
+	return 1
+}
+
 for LDD in ${PATH//://ldd }/ldd; do
 	"$LDD" --version >/dev/null 2>/dev/null && break
 	LDD=""
@@ -150,7 +167,7 @@ for BIN in "$@"; do
 
 	LDSO=""
 
-	[ -n "$LDD" ] && [ -x "$BIN" ] && file "$BIN" | grep -sqE "ELF.*(executable|interpreter)" && {
+	[ -n "$LDD" ] && should_be_patched "$BIN" && {
 		for token in $("$LDD" "$BIN" 2>/dev/null); do
 			case "$token" in */*.so*)
 				dest="$DIR/lib/${token##*/}"