fix: build static fmt too, otherwise we need to append rpaths

.github/workflows/ci.yml

@@ -58,7 +58,7 @@ jobs:
           ref: ${{ env.fmt_version }}
       - name: build
         run: |
-          cmake -S . -B build -DCMAKE_INSTALL_PREFIX=fmt -DBUILD_SHARED_LIBS=TRUE
+          cmake -S . -B build -DCMAKE_INSTALL_PREFIX=fmt -DBUILD_SHARED_LIBS=TRUE -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE
           cmake --build build -j2
           cmake --install build
       - run: brew install tree

doc/setup.md

@@ -27,10 +27,10 @@ python -m pip install meson ninja
 ### :large_orange_diamond: `fmt`: C++ output formatting library
 <https://github.com/fmtlib/fmt>
 - likely available in your package manager, likely as `fmt` or `libfmt`
-- if you compile it yourself, include the `cmake` option `-DBUILD_SHARED_LIBS=TRUE`
+- if you compile it yourself, include the `cmake` options `-DBUILD_SHARED_LIBS=TRUE` and `-DCMAKE_POSITION_INDEPENDENT_CODE=TRUE`
 - example `cmake` commands:
 ```bash
-cmake -S /path/to/fmt_source_code -B build-fmt -DCMAKE_INSTALL_PREFIX=/path/to/fmt_installation -DBUILD_SHARED_LIBS=TRUE
+cmake -S /path/to/fmt_source_code -B build-fmt -DCMAKE_INSTALL_PREFIX=/path/to/fmt_installation -DBUILD_SHARED_LIBS=TRUE -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE
 cmake --build build-fmt -j$(nproc)
 cmake --install build-fmt
 ```