tools: fakeroot: rework relocatable patch to avoid LD_LIBRARY_PATH usage

Due to the use of LD_LIBRARY_PATH, the programs running in the fakeroot
environment may end up loading bundled SDK libraries using the system
ld.so.

Rework the relocatability patch to avoid meddling with LD_LIBRARY_PATH
and construct the paths to faked and libfakeroot.so directly.

Fixes: f93cb5c2c8 ("fakeroot: make fakeroot script relocatable")
Reviewed-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

tools/fakeroot/patches/000-relocatable.patch

@@ -1,25 +1,29 @@
 --- a/scripts/fakeroot.in
 +++ b/scripts/fakeroot.in
-@@ -30,12 +30,19 @@ fatal ()
+@@ -30,13 +30,20 @@ fatal ()
  }
  
  # strip /bin/fakeroot to find install prefix
 -FAKEROOT_PREFIX=@prefix@
 -FAKEROOT_BINDIR=@bindir@
 +if [ -n "$STAGING_DIR_HOST" ]; then
-+    FAKEROOT_PREFIX="${STAGING_DIR_HOST}"
-+    FAKEROOT_BINDIR="${STAGING_DIR_HOST}/bin"
-+    FAKEROOT_LIBDIR="${STAGING_DIR_HOST}/lib"
++    USEABSLIBPATH=1
++    LIB=${STAGING_DIR_HOST}/lib/lib@fakeroot_transformed@@DLSUFFIX@
++    FAKED=${STAGING_DIR_HOST}/bin/faked
++    PATHS=
 +else
 +    FAKEROOT_PREFIX=@prefix@
 +    FAKEROOT_BINDIR=@bindir@
-+    FAKEROOT_LIBDIR=@libdir@
+ 
+-USEABSLIBPATH=@LDPRELOADABS@
+-LIB=lib@fakeroot_transformed@@DLSUFFIX@
+-PATHS=@libdir@:${FAKEROOT_PREFIX}/lib64/libfakeroot:${FAKEROOT_PREFIX}/lib32/libfakeroot
+-FAKED=${FAKEROOT_BINDIR}/@faked_transformed@
++    USEABSLIBPATH=@LDPRELOADABS@
++    LIB=lib@fakeroot_transformed@@DLSUFFIX@
++    PATHS=@libdir@:${FAKEROOT_PREFIX}/lib64/libfakeroot:${FAKEROOT_PREFIX}/lib32/libfakeroot
++    FAKED=${FAKEROOT_BINDIR}/@faked_transformed@
 +fi
  
- USEABSLIBPATH=@LDPRELOADABS@
- LIB=lib@fakeroot_transformed@@DLSUFFIX@
--PATHS=@libdir@:${FAKEROOT_PREFIX}/lib64/libfakeroot:${FAKEROOT_PREFIX}/lib32/libfakeroot
-+PATHS=${FAKEROOT_LIBDIR}:${FAKEROOT_PREFIX}/lib64/libfakeroot:${FAKEROOT_PREFIX}/lib32/libfakeroot
- FAKED=${FAKEROOT_BINDIR}/@faked_transformed@
- 
  FAKED_MODE="unknown-is-root"
+ export FAKED_MODE