treewide: Cleanup usage of multi-arch tools

- Don't needlessly force GCC

 - Prefer using multi-arch stdenvs to using multi-arch tools directly.

pkgs/applications/audio/airwave/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, cmake, fetchFromGitHub, file, gcc_multi, libX11, makeWrapper
+{ stdenv, multiStdenv, cmake, fetchFromGitHub, file, libX11, makeWrapper
 , overrideCC, qt5, requireFile, unzip, wine
 }:
 
@@ -13,8 +13,6 @@ let
     sha256 = "1ban59skw422mak3cp57lj27hgq5d3a4f6y79ysjnamf8rpz9x4s";
   };
 
-  stdenv_multi = overrideCC stdenv gcc_multi;
-
   vst-sdk = stdenv.mkDerivation rec {
     name = "vstsdk368_08_11_2017_build_121";
     src = requireFile {
@@ -38,7 +36,7 @@ let
 
 in
 
-stdenv_multi.mkDerivation {
+multiStdenv.mkDerivation {
   name = "airwave-${version}";
 
   src = airwave-src;
@@ -54,7 +52,7 @@ stdenv_multi.mkDerivation {
     # For airwave-host-32.exe.so, point wineg++ to 32-bit versions of
     # these libraries, as $NIX_LDFLAGS contains only 64-bit ones.
     substituteInPlace src/host/CMakeLists.txt --replace '-m32' \
-      '-m32 -L${wine-xembed}/lib -L${wine-xembed}/lib/wine -L${stdenv_multi.cc.libc.out}/lib/32'
+      '-m32 -L${wine-xembed}/lib -L${wine-xembed}/lib/wine -L${multiStdenv.cc.libc.out}/lib/32'
   '';
 
   # libstdc++.so link gets lost in 64-bit executables during

pkgs/os-specific/linux/statifier/default.nix

@@ -1,7 +1,7 @@
-{ stdenv, fetchurl, gcc_multi, glibc_multi }:
+{ multiStdenv, fetchurl }:
 
 let version = "1.7.4"; in
-stdenv.mkDerivation {
+multiStdenv.mkDerivation {
   name = "statifier-${version}";
 
   src = fetchurl {
@@ -9,16 +9,14 @@ stdenv.mkDerivation {
     sha256 = "03lzkla6knjhh186b43cac410x2fmhi28pkmzb3d211n3zp5i9y8";
   };
 
-  buildInputs = [ gcc_multi glibc_multi ];
-
   phaseNames = [ "patchPhase" "installPhase" ];
 
   postPatch = ''
     sed -e s@/usr/@"$out/"@g -i */Makefile src/statifier
-    sed -e s@/bin/bash@"${stdenv.shell}"@g -i src/*.sh
+    sed -e s@/bin/bash@"${multiStdenv.shell}"@g -i src/*.sh
   '';
 
-  meta = with stdenv.lib; {
+  meta = with multiStdenv.lib; {
     description = "Tool for creating static Linux binaries";
     platforms = platforms.linux;
   };

pkgs/tools/misc/loadlibrary/default.nix

@@ -1,4 +1,4 @@
-{ cabextract, glibc_multi, fetchFromGitHub, readline, stdenv_32bit }:
+{ cabextract, fetchFromGitHub, readline, stdenv_32bit }:
 
 # stdenv_32bit is needed because the program depends upon 32-bit libraries and does not have
 # support for 64-bit yet: it requires libc6-dev:i386, libreadline-dev:i386.
@@ -14,7 +14,7 @@ stdenv_32bit.mkDerivation rec {
     sha256 = "01hb7wzfh1s5b8cvmrmr1gqknpq5zpzj9prq3wrpsgg129jpsjkb";
   };
 
-  buildInputs = [ glibc_multi cabextract readline stdenv_32bit.cc.libc ];
+  buildInputs = [ cabextract readline ];
 
   installPhase = ''
     mkdir -p $out/bin/