diff --git a/pkgs/development/interpreters/octave/default.nix b/pkgs/development/interpreters/octave/default.nix
index 0a87c1ddcf07..e8228d23b0c9 100644
--- a/pkgs/development/interpreters/octave/default.nix
+++ b/pkgs/development/interpreters/octave/default.nix
@@ -184,6 +184,14 @@ let
 
     enableParallelBuilding = true;
 
+    # Fix linker error on Darwin (see https://trac.macports.org/ticket/61865)
+    NIX_LDFLAGS = lib.optionalString stdenv.isDarwin "-lobjc";
+
+    # Avoid Qt 5.12 problem on Big Sur: https://bugreports.qt.io/browse/QTBUG-87014
+    qtWrapperArgs = lib.optionals stdenv.isDarwin [
+      "--set QT_MAC_WANTS_LAYER 1"
+    ];
+
     # See https://savannah.gnu.org/bugs/?50339
     F77_INTEGER_8_FLAG = if use64BitIdx then "-fdefault-integer-8" else "";
 
diff --git a/pkgs/development/libraries/portaudio/default.nix b/pkgs/development/libraries/portaudio/default.nix
index 840c9e773f49..4666850c5849 100644
--- a/pkgs/development/libraries/portaudio/default.nix
+++ b/pkgs/development/libraries/portaudio/default.nix
@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
 
   configureFlags = [ "--disable-mac-universal" "--enable-cxx" ];
 
-  NIX_CFLAGS_COMPILE = lib.optionalString stdenv.cc.isClang "-Wno-error=deprecated-declarations -Wno-error=implicit-const-int-float-conversion -Wno-error=nullability-completeness-on-arrays";
+  NIX_CFLAGS_COMPILE = lib.optionalString stdenv.cc.isClang "-Wno-error=deprecated-declarations -Wno-error=nullability-completeness-on-arrays";
 
   propagatedBuildInputs = lib.optionals stdenv.isDarwin [ AudioUnit AudioToolbox CoreAudio CoreServices Carbon ];