Duplicate passing of gcc-options

[jasagredo]

Describe the bug

I like having these in my cabal config to suppress some warnings:

  gcc-options: -Wl,--allow-multiple-definition -Wno-pragma-pack -Wno-macro-redefined -Wno-missing-declarations

Building with verbose output shows that cabal duplicates these options when calling the C compiler:

$ cabal build -v3 | grep allow
...
["act-as-setup","--build-type=Simple",...,"--gcc-option=-Wl,--allow-multiple-definition","--gcc-option=-Wno-pragma-pack","--gcc-option=-Wno-macro-redefined","--gcc-option=-Wno-missing-declarations","--gcc-option=-Wl,--allow-multiple-definition","--gcc-option=-Wno-pragma-pack","--gcc-option=-Wno-macro-redefined","--gcc-option=-Wno-missing-declarations","--ghc-option=-hide-all-packages",...]
--gcc-option=-Wl,--allow-multiple-definition --gcc-option=-Wno-pragma-pack
--gcc-option=-Wl,--allow-multiple-definition --gcc-option=-Wno-pragma-pack
...
Running: "C:\ghcup\ghc\9.6.6\lib\../mingw/bin\clang.exe" ... "-Wl,--allow-multiple-definition" "-Wno-pragma-pack" "-Wno-macro-redefined" "-Wno-missing-declarations" "-Wl,--allow-multiple-definition" "-Wno-pragma-pack" "-Wno-macro-redefined" "-Wno-missing-declarations"

Cabal used: 3.14

[jasagredo]

I investigated this a bit more and found out that for the list of program-default-options we duplicate the previous existing list of args, so for example:

program-default-options
  alex-options: -foo -bar

will result in --alex-option=-foo --alex-option=-bar but

program-default-options
  alex-options: -foo -bar
  ar-options: -baz

will result in --alex-option=-foo --alex-option=-bar --alex-option=-foo --alex-option=-bar --ar-option=-baz

And so on. No matter if we don't use the program in question (I checked with greencard-options which I'm sure I don't use)