cc-wrapper: Clean up dynamic linking with x86 multilib

It's better layering to do everything in ld-wrapper.

pkgs/build-support/cc-wrapper/cc-wrapper.sh

@@ -57,10 +57,6 @@ while (( "$n" < "$nParams" )); do
         cppInclude=0
     elif [ "${p:0:1}" != - ]; then
         nonFlagArgs=1
-    elif [ "$p" = -m32 ]; then
-        if [ -e @out@/nix-support/dynamic-linker-m32 ]; then
-            NIX_@infixSalt@_LDFLAGS+=" -dynamic-linker $(< @out@/nix-support/dynamic-linker-m32)"
-        fi
     fi
     n+=1
 done

pkgs/build-support/cc-wrapper/ld-wrapper.sh

@@ -63,6 +63,21 @@ fi
 
 extraAfter+=($NIX_@infixSalt@_LDFLAGS_AFTER)
 
+# Choose 32-bit dynamic linker if needed
+if [ -e @out@/nix-support/dynamic-linker-m32 ]; then
+    prev=
+    for p in ${params+"${params[@]}"}; do
+        if [[ "$prev" = "-m" && "$p" = "elf_i386" ]]; then
+           extraAfter+=(
+               '-dynamic-linker'
+               "$(< @out@/nix-support/dynamic-linker-m32)"
+           )
+           break
+        fi
+        prev="$p"
+    done
+fi
+
 declare -a libDirs
 declare -A libs
 relocatable=