Patch the Gleam formatter to fix the indentation. For the Arch Linux PKGBUILD.

patch-gleam-format.sh

# git clone https://aur.archlinux.org/gleam.git

pkgver="1.0.0"
EDITOR=${EDITOR:-micro}

makepkg --nobuild
cd src/
cp -r gleam-$pkgver gleam-$pkgver-new
$EDITOR gleam-$pkgver-new/compiler-core/src/format.rs
# - const INDENT: isize = 2;
# + const INDENT: isize = 3;
diff --unified --recursive --text gleam-$pkgver gleam-$pkgver-new > ../INDENT.patch
$EDITOR ../INDENT.patch
cd ../
$EDITOR PKGBUILD
# Add ` "INDENT.patch"` to source:
# Add ` 'SKIP'` to sha256sums and sha512sums
# Add this to prepare:
# patch --forward --strip=1 --input=../INDENT.patch
makepkg --nobuild -c
makepkg -si