mail/thunderbird: fix build on powerpc64

  12537 /wrkdirs/usr/ports/mail/thunderbird/work/thunderbird-91.2.0/dom/media/flac/FlacDecoder.cpp:21:20: error: no matching member function for call to 'SupportsMimeType'
  12538          platform->SupportsMimeType("audio/flac"_ns,
  12539          ~~~~~~~~~~^~~~~~~~~~~~~~~~
  12540 /wrkdirs/usr/ports/mail/thunderbird/work/.build/dist/include/PDMFactory.h:85:15: note: candidate function not viable: no known conversion from 'nullptr_t' to 'const mozilla::PDMFactory::MediaCodecsSupported' (aka 'const EnumSet<mozilla::PDMFactory::MediaCodecs>') for 2nd argument
  12541   static bool SupportsMimeType(const nsACString& aMimeType,
  12542               ^
  12543 /wrkdirs/usr/ports/mail/thunderbird/work/.build/dist/include/PDMFactory.h:47:8: note: candidate function not viable: requires single argument 'aMimeType', but 2 arguments were provided
  12544   bool SupportsMimeType(const nsACString& aMimeType) const;

mail/thunderbird/files/patch-dom_media_flac_FlacDecoder.cpp

@@ -1,8 +1,6 @@
 Enable FLAC on platforms without ffvpx like powerpc*
 
-diff --git dom/media/flac/FlacDecoder.cpp dom/media/flac/FlacDecoder.cpp
-index 53fc3c9937f7..b23771ab80fa 100644
---- dom/media/flac/FlacDecoder.cpp
+--- dom/media/flac/FlacDecoder.cpp.orig	2021-04-15 19:44:28 UTC
 +++ dom/media/flac/FlacDecoder.cpp
 @@ -7,6 +7,7 @@
  #include "FlacDecoder.h"
@@ -12,15 +10,14 @@ index 53fc3c9937f7..b23771ab80fa 100644
 
  namespace mozilla {
 
-@@ -14,6 +15,11 @@ namespace mozilla {
+@@ -14,6 +15,10 @@ namespace mozilla {
  bool FlacDecoder::IsEnabled() {
  #ifdef MOZ_FFVPX
    return StaticPrefs::media_flac_enabled();
 +#elif defined(MOZ_FFMPEG)
 +  RefPtr<PDMFactory> platform = new PDMFactory();
 +  return StaticPrefs::media_flac_enabled() &&
-+         platform->SupportsMimeType(NS_LITERAL_CSTRING("audio/flac"),
-+                                    /* DecoderDoctorDiagnostics* */ nullptr);
++         platform->SupportsMimeType("audio/flac"_ns);
  #else
-   // Until bug 1295886 is fixed.
    return false;
+ #endif