vapoursynthPlugins: set libdir in meson config

This replaces the custom installPhase.

plugins/addgrain/default.nix

@@ -14,12 +14,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth ];
 
-  installPhase =
-    let
-      ext = stdenv.targetPlatform.extensions.sharedLibrary;
-    in ''
-      install -D libaddgrain${ext} $out/lib/vapoursynth/libaddgrain${ext}
-    '';
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
 
   meta = with lib; {
     description = "AddGrain filter for VapourSynth";

plugins/bm3d/default.nix

@@ -14,14 +14,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth fftwSinglePrec ];
 
-  # i could not find a way to override the default meson install dir.
-  # patching the file didn't work
-  installPhase =
-    let
-      ext = stdenv.targetPlatform.extensions.sharedLibrary;
-    in ''
-      install -D libbm3d${ext} $out/lib/vapoursynth/libbm3d${ext}
-    '';
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
 
   meta = with lib; {
     description = "BM3D denoising filter for VapourSynth";

plugins/eedi2/default.nix

@@ -14,12 +14,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth ];
 
-  installPhase =
-    let
-      ext = stdenv.targetPlatform.extensions.sharedLibrary;
-    in ''
-      install -D libeedi2${ext} $out/lib/vapoursynth/libeedi2${ext}
-    '';
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
 
   meta = with lib; {
     description = "EEDI2 filter for VapourSynth";

plugins/eedi3m/default.nix

@@ -14,12 +14,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth boost opencl-headers ocl-icd ];
 
-  installPhase =
-    let
-      ext = stdenv.targetPlatform.extensions.sharedLibrary;
-    in ''
-      install -D libeedi3m${ext} $out/lib/vapoursynth/libeedi3m${ext}
-    '';
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
 
   meta = with lib; {
     description = "Renewed EEDI3 filter for VapourSynth";

plugins/retinex/default.nix

@@ -14,6 +14,11 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth ];
 
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
+
   installPhase =
     let
       ext = stdenv.targetPlatform.extensions.sharedLibrary;

plugins/tcanny/default.nix

@@ -14,12 +14,10 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ meson ninja pkg-config ];
   buildInputs = [ vapoursynth boost opencl-headers ocl-icd ];
 
-  installPhase =
-    let
-      ext = stdenv.targetPlatform.extensions.sharedLibrary;
-    in ''
-      install -D libtcanny${ext} $out/lib/vapoursynth/libtcanny${ext}
-    '';
+  postPatch = ''
+    substituteInPlace meson.build \
+        --replace "vapoursynth_dep.get_pkgconfig_variable('libdir')" "get_option('libdir')"
+  '';
 
   meta = with lib; {
     description = "TCanny filter for VapourSynth";