treewide: use --set-default and --set-eval where appropriate

pkgs/development/compilers/dmd/2.067.1.nix

@@ -146,7 +146,7 @@ stdenv.mkDerivation rec {
 
       wrapProgram $out/bin/dmd \
           --prefix PATH ":" "${stdenv.cc}/bin" \
-          --set CC "$""{CC:-$CC""}"
+          --set-default CC "$CC"
 
       cd $out/bin
       tee dmd.conf << EOF

pkgs/development/compilers/dmd/default.nix

@@ -152,7 +152,7 @@ stdenv.mkDerivation rec {
 
       wrapProgram $out/bin/dmd \
           --prefix PATH ":" "${stdenv.cc}/bin" \
-          --set CC "$""{CC:-$CC""}"
+          --set-default CC "$CC"
 
       cd $out/bin
       tee dmd.conf << EOF

pkgs/misc/emulators/retrofe/default.nix

@@ -65,7 +65,7 @@ stdenv.mkDerivation rec {
   postInstall = ''
     wrapProgram "$out/bin/retrofe" \
       --prefix GST_PLUGIN_PATH : "$GST_PLUGIN_SYSTEM_PATH_1_0" \
-      --set    RETROFE_PATH      "\''${RETROFE_PATH:-\$PWD}"
+      --set-eval RETROFE_PATH '$''\{RETROFE_PATH:-$PWD}'
   '';
 
   meta = with stdenv.lib; {

pkgs/servers/nosql/apache-jena/fuseki-binary.nix

@@ -24,7 +24,7 @@ stdenv.mkDerivation {
     for i in "$out"/bin/*; do
       wrapProgram "$i" \
         --prefix "PATH" : "${java}/bin/" \
-        --set "FUSEKI_HOME" '"''${FUSEKI_HOME:-'"$out"'}"' \
+        --set-default "FUSEKI_HOME" "$out" \
         ;
     done
   '';

pkgs/tools/text/popfile/default.nix

@@ -44,8 +44,8 @@ stdenv.mkDerivation rec {
       wrapProgram "$path" \
         --prefix PERL5LIB : $PERL5LIB:$out/bin \
         --set POPFILE_ROOT $out/bin \
-        --set POPFILE_USER \$\{POPFILE_USER:-\$HOME/.popfile\} \
-        --run "test -d \$POPFILE_USER || mkdir -m 0700 -p \$POPFILE_USER"
+        --set-eval POPFILE_USER '$''\{POPFILE_USER:-$HOME/.popfile}' \
+        --run 'test -d "$POPFILE_USER" || mkdir -m 0700 -p "$POPFILE_USER"'
     done
   '';