Add comment to clarify git-lfs build hack

script/build-macos.sh

@@ -76,8 +76,15 @@ if [[ "$GIT_LFS_VERSION" ]]; then
   git clone -b "v$GIT_LFS_VERSION" "https://github.com/git-lfs/git-lfs"
   (
     cd git-lfs
+
+    # HACK: When cross-compiling, there seems to be an issue when git-lfs attempts
+    # to generate the manpage contents, and it seems that preffixing that command
+    # with `GOARCH=` to use the host architecture fixes the issue.
+    # This hack can be removed once the issue is fixed via the PR
+    # https://github.com/git-lfs/git-lfs/pull/4492 or some other solution.
     GO_GENERATE_STRING="\$(GO) generate github.com\/git-lfs\/git-lfs\/commands"
     sed -i -e "s/$GO_GENERATE_STRING/GOARCH= $GO_GENERATE_STRING/" Makefile
+
     make GOARCH="$GOARCH" CGO_CFLAGS="-mmacosx-version-min=$MACOSX_BUILD_VERSION" CGO_LDFLAGS="-mmacosx-version-min=$MACOSX_BUILD_VERSION" BUILTIN_LD_FLAGS="-linkmode external"
   )
   GIT_LFS_BINARY_PATH="git-lfs/bin/git-lfs"