pkgconfig: fix cygwin build

pkgs/development/tools/misc/pkgconfig/2.36.3-not-win32.patch

@@ -309,3 +309,16 @@
  # else
  
    /* On old systems which lack it, use setlocale or getenv.  */
+diff --git a/glib/gtypes.h b/glib/gtypes.h
+index c18e0bf..816685a 100644
+--- a/glib/glib/gtypes.h
++++ b/glib/glib/gtypes.h
+@@ -462,7 +462,7 @@ G_END_DECLS
+  * properly get exported in Windows DLLs.
+  */
+ #ifndef GLIB_VAR
+-#  ifdef G_PLATFORM_WIN32
++#  ifdef G_OS_WIN32
+ #    ifdef GLIB_STATIC_COMPILATION
+ #      define GLIB_VAR extern
+ #    else /* !GLIB_STATIC_COMPILATION */

pkgs/development/tools/misc/pkgconfig/default.nix

@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
   configureFlags = [ "--with-internal-glib" ]
     ++ optional (stdenv.isSunOS) [ "--with-libiconv=gnu" "--with-system-library-path" "--with-system-include-path" "CFLAGS=-DENABLE_NLS" ];
 
-  postInstall = ''rm "$out"/bin/*-pkg-config''; # clean the duplicate file
+  postInstall = ''rm -f "$out"/bin/*-pkg-config''; # clean the duplicate file
 
   meta = {
     description = "A tool that allows packages to find out information about other packages";