ghc: don't build with profiling on aarch64 #66277

This makes ghc output be lower than 2GB limit.

Also enable aarch64 build parallelism now that it's fixed in GHC 8.6

pkgs/development/compilers/ghc/8.8.3.nix

@@ -30,6 +30,9 @@
 , # Whether to build terminfo.
   enableTerminfo ? !stdenv.targetPlatform.isWindows
 
+  # aarch64 outputs otherwise exceed 2GB limit
+, enableProfiliedLibs ? !stdenv.targetPlatform.isAarch64
+
 , # What flavour to build. An empty string indicates no
   # specific flavour and falls back to ghc default values.
   ghcFlavour ? stdenv.lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
@@ -65,6 +68,8 @@ let
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
     BUILD_SPHINX_PDF = NO
+  '' + stdenv.lib.optionalString (!enableProfiliedLibs) ''
+    GhcLibWays = "v dyn"
   '' + stdenv.lib.optionalString enableRelocatedStaticLibs ''
     GhcLibHcOpts += -fPIC
     GhcRtsHcOpts += -fPIC

pkgs/development/haskell-modules/generic-builder.nix

@@ -27,7 +27,8 @@ in
 , doHoogle ? true
 , doHaddockQuickjump ? doHoogle && stdenv.lib.versionAtLeast ghc.version "8.6"
 , editedCabalFile ? null
-, enableLibraryProfiling ? !(ghc.isGhcjs or false)
+# aarch64 outputs otherwise exceed 2GB limit
+, enableLibraryProfiling ? !(ghc.isGhcjs or stdenv.targetPlatform.isAarch64 or false)
 , enableExecutableProfiling ? false
 , profilingDetail ? "exported-functions"
 # TODO enable shared libs for cross-compiling
@@ -48,8 +49,7 @@ in
 , isExecutable ? false, isLibrary ? !isExecutable
 , jailbreak ? false
 , license
-  # aarch64 sometimes crashes for -jn with n>1: https://ghc.haskell.org/trac/ghc/ticket/15449
-, enableParallelBuilding ? !stdenv.buildPlatform.isAarch64
+, enableParallelBuilding ? true
 , maintainers ? []
 , doCoverage ? false
 , doHaddock ? !(ghc.isHaLVM or false)