bintools-wrapper: Add `sharedLibraryLoader` parameter

This is used instead of `libc_lib` in case the shared library loader /
"interpreter" is not provided by the libc derivation.

pkgs/build-support/bintools-wrapper/default.nix

@@ -9,6 +9,7 @@
 , lib
 , stdenvNoCC
 , bintools ? null, libc ? null, coreutils ? null, shell ? stdenvNoCC.shell, gnugrep ? null
+, sharedLibraryLoader ? if libc == null then null else lib.getLib libc
 , nativeTools, noLibc ? false, nativeLibc, nativePrefix ? ""
 , propagateDoc ? bintools != null && bintools ? man
 , extraPackages ? [], extraBuildCommands ? ""
@@ -54,19 +55,19 @@ let
   # The dynamic linker has different names on different platforms. This is a
   # shell glob that ought to match it.
   dynamicLinker =
-    /**/ if libc == null then null
-    else if targetPlatform.libc == "musl"             then "${libc_lib}/lib/ld-musl-*"
+    /**/ if sharedLibraryLoader == null then null
+    else if targetPlatform.libc == "musl"             then "${sharedLibraryLoader}/lib/ld-musl-*"
     else if (targetPlatform.libc == "bionic" && targetPlatform.is32bit) then "/system/bin/linker"
     else if (targetPlatform.libc == "bionic" && targetPlatform.is64bit) then "/system/bin/linker64"
-    else if targetPlatform.libc == "nblibc"           then "${libc_lib}/libexec/ld.elf_so"
-    else if targetPlatform.system == "i686-linux"     then "${libc_lib}/lib/ld-linux.so.2"
-    else if targetPlatform.system == "x86_64-linux"   then "${libc_lib}/lib/ld-linux-x86-64.so.2"
-    else if targetPlatform.system == "powerpc64le-linux" then "${libc_lib}/lib/ld64.so.2"
+    else if targetPlatform.libc == "nblibc"           then "${sharedLibraryLoader}/libexec/ld.elf_so"
+    else if targetPlatform.system == "i686-linux"     then "${sharedLibraryLoader}/lib/ld-linux.so.2"
+    else if targetPlatform.system == "x86_64-linux"   then "${sharedLibraryLoader}/lib/ld-linux-x86-64.so.2"
+    else if targetPlatform.system == "powerpc64le-linux" then "${sharedLibraryLoader}/lib/ld64.so.2"
     # ARM with a wildcard, which can be "" or "-armhf".
-    else if (with targetPlatform; isAarch32 && isLinux)   then "${libc_lib}/lib/ld-linux*.so.3"
-    else if targetPlatform.system == "aarch64-linux"  then "${libc_lib}/lib/ld-linux-aarch64.so.1"
-    else if targetPlatform.system == "powerpc-linux"  then "${libc_lib}/lib/ld.so.1"
-    else if targetPlatform.isMips                     then "${libc_lib}/lib/ld.so.1"
+    else if (with targetPlatform; isAarch32 && isLinux)   then "${sharedLibraryLoader}/lib/ld-linux*.so.3"
+    else if targetPlatform.system == "aarch64-linux"  then "${sharedLibraryLoader}/lib/ld-linux-aarch64.so.1"
+    else if targetPlatform.system == "powerpc-linux"  then "${sharedLibraryLoader}/lib/ld.so.1"
+    else if targetPlatform.isMips                     then "${sharedLibraryLoader}/lib/ld.so.1"
     else if targetPlatform.isDarwin                   then "/usr/lib/dyld"
     else if targetPlatform.isFreeBSD                  then "/libexec/ld-elf.so.1"
     else if lib.hasSuffix "pc-gnu" targetPlatform.config then "ld.so.1"
@@ -224,10 +225,10 @@ stdenv.mkDerivation {
     ##
     ## Dynamic linker support
     ##
-    + ''
+    + optionalString (sharedLibraryLoader != null) ''
       if [[ -z ''${dynamicLinker+x} ]]; then
         echo "Don't know the name of the dynamic linker for platform '${targetPlatform.config}', so guessing instead." >&2
-        local dynamicLinker="${libc_lib}/lib/ld*.so.?"
+        local dynamicLinker="${sharedLibraryLoader}/lib/ld*.so.?"
       fi
     ''
 
@@ -246,9 +247,9 @@ stdenv.mkDerivation {
 
         ${if targetPlatform.isDarwin then ''
           printf "export LD_DYLD_PATH=%q\n" "$dynamicLinker" >> $out/nix-support/setup-hook
-        '' else ''
-          if [ -e ${libc_lib}/lib/32/ld-linux.so.2 ]; then
-            echo ${libc_lib}/lib/32/ld-linux.so.2 > $out/nix-support/dynamic-linker-m32
+        '' else lib.optionalString (sharedLibraryLoader != null) ''
+          if [ -e ${sharedLibraryLoader}/lib/32/ld-linux.so.2 ]; then
+            echo ${sharedLibraryLoader}/lib/32/ld-linux.so.2 > $out/nix-support/dynamic-linker-m32
           fi
           touch $out/nix-support/ld-set-dynamic-linker
         ''}