Missing compilation instructions

2025/day07/README.md

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+# Day 07: Haskell
+
+This one took me the longest, mostly because I really do not know Haskell. Nevertheless, I find the
+resulting solution quite elegant. The `Makefile` I made uses dynamic linkage as that's how Haskell
+works on Arch Linux. If you want to do static linking, `ghc solve.hs` should work.
+
+```console
+$ make
+ghc -dynamic -O -g -o solve solve.hs
+[1 of 2] Compiling Main             ( solve.hs, solve.o )
+[2 of 2] Linking solve
+$ ./solve sample.txt
+21
+40
+```