gcc: fix powerpc-linux cross compilers

pkgs/development/compilers/gcc/common/libgcc-buildstuff.nix

@@ -16,7 +16,7 @@ let
   # glibc.  At this early pre-glibc stage these files sometimes
   # have different names.
   crtstuff-ofiles =
-    if stdenv.targetPlatform.isPower then "ecrti.o ecrtn.o ncrti.o ncrtn.o" else "crti.o crtn.o";
+    if stdenv.targetPlatform.isPower64 then "ecrti.o ecrtn.o ncrti.o ncrtn.o" else "crti.o crtn.o";
 
   # Normally, `SHLIB_LC` is set to `-lc`, which means that
   # `libgcc_s.so` cannot be built until `libc.so` is available.
@@ -28,7 +28,7 @@ let
   # gcc-built `{e,n}crt{n,i}.o` instead of failing to find the
   # versions which have been repackaged in libc as `crt{n,i}.o`
   #
-  SHLIB_LC = lib.optionalString stdenv.targetPlatform.isPower "-mnewlib";
+  SHLIB_LC = lib.optionalString stdenv.targetPlatform.isPower64 "-mnewlib";
 
 in
 ''
@@ -47,11 +47,14 @@ in
 # https://www.openwall.com/lists/musl/2022/11/09/3
 #
 # 'parsed.cpu.family' won't be correct for every platform.
-+
-  lib.optionalString
-    (
-      stdenv.targetPlatform.isLoongArch64 || stdenv.targetPlatform.isS390 || stdenv.targetPlatform.isAlpha
-    )
-    ''
-      touch libgcc/config/${stdenv.targetPlatform.parsed.cpu.family}/crt{i,n}.S
-    ''
++ (lib.optionalString
+  (
+    stdenv.targetPlatform.isLoongArch64 || stdenv.targetPlatform.isS390 || stdenv.targetPlatform.isAlpha
+  )
+  ''
+    touch libgcc/config/${stdenv.targetPlatform.parsed.cpu.family}/crt{i,n}.S
+  ''
+)
++ lib.optionalString (stdenv.targetPlatform.isPower && !stdenv.targetPlatform.isPower64) ''
+  touch libgcc/config/rs6000/crt{i,n}.S
+''