Remove trailing whitespaces and fix indentation

pkgs/development/compilers/gcc/common/configure-flags.nix

@@ -73,7 +73,7 @@ let
       "--enable-libssp"
       "--disable-nls"
       # To keep ABI compatibility with upstream mingw-w64
-      "--enable-fully-dynamic-string"      
+      "--enable-fully-dynamic-string"
     ] ++ lib.optionals (crossMingw && targetPlatform.isx86_32) [
       # See Note [Windows Exception Handling]
       "--enable-sjlj-exceptions"
@@ -187,10 +187,10 @@ let
       "--disable-symvers"
       "libat_cv_have_ifunc=no"
       "--disable-gnu-indirect-function"
-    ] 
+    ]
     ++ lib.optionals langJit [
       "--enable-host-shared"
-    ] 
+    ]
     ++ lib.optionals (langD) [
       "--with-target-system-zlib=yes"
     ]