cc-wrapper: expand response files

Fixes #11762

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

@@ -23,7 +23,7 @@ getVersion=0
 nonFlagArgs=0
 [[ "@prog@" = *++ ]] && isCpp=1 || isCpp=0
 
-params=("$@")
+expandResponseParams "$@"
 n=0
 while [ $n -lt ${#params[*]} ]; do
     p=${params[n]}

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

@@ -16,7 +16,7 @@ source @out@/nix-support/utils.sh
 
 
 # Optionally filter out paths not refering to the store.
-params=("$@")
+expandResponseParams "$@"
 if [ "$NIX_ENFORCE_PURITY" = 1 -a -n "$NIX_STORE" \
         -a \( -z "$NIX_IGNORE_LD_THROUGH_GCC" -o -z "$NIX_LDFLAGS_SET" \) ]; then
     rest=()

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

@@ -22,3 +22,27 @@ badPath() {
         "${p:0:4}" != "/tmp" -a \
         "${p:0:${#NIX_BUILD_TOP}}" != "$NIX_BUILD_TOP"
 }
+
+expandResponseParams() {
+    local inparams=("$@")
+    local n=0
+    local p
+    params=()
+    while [ $n -lt ${#inparams[*]} ]; do
+        p=${inparams[n]}
+        case $p in
+            @*)
+                if [ -e "${p:1}" ]; then
+                    args=$(<"${p:1}")
+                    eval 'for arg in '$args'; do params+=("$arg"); done'
+                else
+                    params+=("$p")
+                fi
+                ;;
+            *)
+                params+=("$p")
+                ;;
+        esac
+        n=$((n + 1))
+    done
+}