diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 04a1a9f79..d4f5c7b4e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -131,6 +131,69 @@ jobs:
         run: |
           make docker-test-dist
 
+  build-macos:
+    name: Build macOS
+    runs-on: macos-latest
+    env:
+      CFLAGS: "-I/opt/homebrew/include/luajit-2.1 -I/opt/homebrew/include"
+      OBJCFLAGS: "-I/opt/homebrew/include/luajit-2.1 -I/opt/homebrew/include"
+      LDFLAGS: "-L/opt/homebrew/lib"
+      DOCKER: false
+      LDOC: false
+      NIX: false
+      SHA256SUM: false
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Cache test fonts
+        uses: actions/cache@v4
+        with:
+          path: |
+            .fonts
+            .sources
+          key: fonts-${{ hashFiles('Makefile-fonts') }}
+      - name: Cache lua_modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            lua_modules
+          key: luarocks-${{ hashFiles('Makefile-luarocks', 'sile.rockspec.in') }}
+      - name: Install system dependencies
+        run: |
+          brew install \
+            autoconf \
+            automake \
+            expat \
+            ghostscript \
+            graphviz \
+            libtool \
+            luajit \
+            luarocks \
+            poppler \
+            rust \
+            unzip \
+            zlib
+          brew link icu4c@76 --force
+          brew link zlib --force
+          brew link expat --force
+          brew install --cask font-gentium-plus
+      - name: Configure
+        run: |
+          ./bootstrap.sh
+          ./configure \
+            --enable-developer-mode \
+            --without-developer-tools \
+            --with-system-lua-sources \
+            --with-manual
+          echo "VERSION=$(./build-aux/git-version-gen .tarball-version)" >> $GITHUB_ENV
+          # Note don't use -Otarget for macOS, Homebrew's old make is too buggy
+          echo "MAKEFLAGS=-j$(sysctl -n hw.ncpu)" >> $GITHUB_ENV
+      - name: Make
+        run: |
+          make
+
   build-nix:
     runs-on: ubuntu-22.04
     name: Build Nix
diff --git a/Makefile.am b/Makefile.am
index c43a302d8..19ba5b72f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -56,7 +56,6 @@ endif
 $(MANUAL): $(FIGURES)
 
 BUILT_SOURCES_LUA = core/features.lua core/pathsetup.lua core/version.lua
-RUSILE_SOURCES = rusile/Cargo.toml rusile/src/lib.rs
 
 bin_PROGRAMS = sile
 bin_SCRIPTS = sile-lua
@@ -67,8 +66,6 @@ EXTRA_sile_SOURCES =
 if !EMBEDDED_RESOURCES
 nobase_dist_pkgdata_DATA = $(SILEDATA) $(LUALIBRARIES)
 nobase_nodist_pkgdata_DATA = $(BUILT_SOURCES_LUA) $(LUAMODULES)
-pkglib_LIBRARIES = rusile.so
-rusile_so_SOURCES = $(RUSILE_SOURCES)
 endif !EMBEDDED_RESOURCES
 dist_doc_DATA = README.md CHANGELOG.md
 dist_pdf_DATA = $(_MANUAL)
@@ -137,7 +134,7 @@ $(CARGO_BIN): justenough/.libs/justenoughlibtexpdf.a
 $(CARGO_BIN): justenough/.libs/svg.a
 $(CARGO_BIN): libtexpdf/.libs/libtexpdf.a
 if !EMBEDDED_RESOURCES
-$(CARGO_BIN): rusile.so
+$(CARGO_BIN): rusile.$(SHARED_LIB_EXT)
 endif !EMBEDDED_RESOURCES
 
 src/embed-includes.rs: Makefile-distfiles
@@ -164,7 +161,7 @@ else
 MLUAVER = lua$(LUA_SHORT_VERSION)
 endif
 CARGO_FEATURE_ARGS = --features $(MLUAVER)
-RUSILE_FEATURE_ARG = --features $(MLUAVER)
+rusile_FEATURE_ARGS = --features $(MLUAVER)
 
 if !SYSTEM_LUA_SOURCES
 CARGO_FEATURE_ARGS += --features vendored
@@ -178,10 +175,6 @@ if FONT_VARIATIONS
 CARGO_FEATURE_ARGS += --features variations
 endif
 
-rusile.so: $(rusile_so_SOURCES) $(bin_PROGRAMS)
-	$(CARGO_ENV) $(CARGO) build $(CARGO_VERBOSE) --target $(CARGO_TARGET_TRIPLE) $(RUSILE_FEATURE_ARG) $(CARGO_RELEASE_ARGS) -p rusile
-	$(INSTALL) @builddir@/target/@RUST_TARGET_SUBDIR@/lib$@ $@
-
 DEPDIR := .deps
 LOCALFONTS := FONTCONFIG_FILE=$(PWD)/fontconfig.conf
 LOCALPATHS := SILE_PATH="$(PWD);libtexpdf/.libs;justenough/.libs"
diff --git a/build-aux/module.rs b/build-aux/module.rs
new file mode 100644
index 000000000..e10b0cdcd
--- /dev/null
+++ b/build-aux/module.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("cargo:rustc-link-arg=-Wl,-undefined,dynamic_lookup");
+}
diff --git a/build-aux/que_rust_boilerplate.m4 b/build-aux/que_rust_boilerplate.m4
index bc3d5ffaf..050afbf4e 100644
--- a/build-aux/que_rust_boilerplate.m4
+++ b/build-aux/que_rust_boilerplate.m4
@@ -44,3 +44,14 @@ $($SED -E "s/@PACKAGE_VAR@/$PACKAGE_VAR/g;s/@PACKAGE_NAME@/$PACKAGE_NAME/g" buil
 ])dnl
 
 ])
+
+AC_DEFUN([QUE_RUST_MODULE], [
+
+        AC_REQUIRE([AX_AM_MACROS])
+        AX_ADD_AM_MACRO([dnl
+EXTRA_DIST += build-aux/que_rust_module.am
+
+$($SED -E "s/@MODULE@/$1/g;s/@SHARED_LIB_EXT@/$SHARED_LIB_EXT/g" build-aux/que_rust_module.am)
+])dnl
+
+])
diff --git a/build-aux/que_rust_module.am b/build-aux/que_rust_module.am
new file mode 100644
index 000000000..708b6a12b
--- /dev/null
+++ b/build-aux/que_rust_module.am
@@ -0,0 +1,8 @@
+pkglib_LIBRARIES = @MODULE@.@SHARED_LIB_EXT@
+@MODULE@_@SHARED_LIB_EXT@_SOURCES = @MODULE@/Cargo.toml @MODULE@/src/lib.rs build-aux/module.rs
+
+@builddir@/target/@RUST_TARGET_SUBDIR@/lib@MODULE@.@SHARED_LIB_EXT@: $(@MODULE@_@SHARED_LIB_EXT@_SOURCES)
+	$(CARGO_ENV) $(CARGO) build $(CARGO_VERBOSE) --target $(CARGO_TARGET_TRIPLE) $(@MODULE@_FEATURE_ARGS) $(CARGO_RELEASE_ARGS) -p @MODULE@
+
+@MODULE@.@SHARED_LIB_EXT@: @builddir@/target/@RUST_TARGET_SUBDIR@/lib@MODULE@.@SHARED_LIB_EXT@
+	$(INSTALL) $< $@
diff --git a/configure.ac b/configure.ac
index ac639e639..bd55b7a09 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,6 +2,7 @@ AC_PREREQ([2.69])
 AC_INIT([sile], [m4_esyscmd(build-aux/git-version-gen .tarball-version)], [caleb@alerque.com])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([build-aux])
+AC_CANONICAL_TARGET
 AM_INIT_AUTOMAKE([foreign tar-pax dist-zstd dist-zip no-dist-gzip color-tests subdir-objects])
 AM_SILENT_RULES([yes])
 
@@ -37,11 +38,24 @@ RANLIB=:
 LT_PREREQ([2.2])
 LT_INIT([dlopen])
 
-AC_CANONICAL_HOST
-
 QUE_RUST_BOILERPLATE
 QUE_DOCKER_BOILERPLATE
 
+# Load Rust module bits, early since it stuffs rules in aminclude.am
+case $target_os in
+    darwin*)
+        SHARED_LIB_EXT="dylib"
+        ;;
+    cygwin*|mingw*)
+        SHARED_LIB_EXT="dll"
+        ;;
+    *)
+        SHARED_LIB_EXT="so"
+        ;;
+esac
+AC_SUBST([SHARED_LIB_EXT])
+QUE_RUST_MODULE([rusile])
+
 AM_CONDITIONAL([SHARED], [test "x$enable_shared" = "xyes"])
 AM_CONDITIONAL([STATIC], [test "x$enable_static" = "xyes"])
 
@@ -111,7 +125,7 @@ AM_COND_IF([MANUAL], [
 
 AC_MSG_CHECKING([for OS X])
 have_appkit=no
-case $host_os in
+case $target_os in
     darwin*)
         AC_MSG_RESULT([yes])
         AC_MSG_CHECKING([for AppKit works])
@@ -244,20 +258,6 @@ AC_SUBST([HARFBUZZ_SUBSET_LIBS])
 AC_SUBST([ICU_TRUE])
 AC_SUBST([ICU_CFLAGS])
 AC_SUBST([ICU_LIBS])
-
-case $host_os in
-    darwin*)
-        LUAROCKSARGS="EXPAT_DIR=/usr/local/opt/expat OPENSSL_DIR=/usr/local/opt/openssl ZLIB_DIR=/usr/local/opt/zlib"
-        SHARED_LIB_EXT="so"
-        ;;
-    cygwin*|mingw*)
-        SHARED_LIB_EXT="dll"
-        ;;
-    *)
-        SHARED_LIB_EXT="so"
-        ;;
-esac
-AC_SUBST([SHARED_LIB_EXT])
 AC_SUBST([LUAROCKSARGS])
 
 # Avoid need for `--datarootdir=$(cd ..; pwd)` hack to run locally for
diff --git a/core/cli.lua b/core/cli.lua
index f5a2135d3..d9dbced06 100644
--- a/core/cli.lua
+++ b/core/cli.lua
@@ -73,7 +73,7 @@ cli.parseArguments = function ()
       SILE.input.filenames = opts.INPUTS
    end
    if opts.backend then
-      SILE.backend = opts.backend
+      SILE.input.backend = opts.backend
    end
    if opts.class then
       SILE.input.class = opts.class
@@ -90,7 +90,7 @@ cli.parseArguments = function ()
       table.insert(SILE.input.evaluateAfters, statement)
    end
    if opts.fontmanager then
-      SILE.forceFontManager = opts.fontmanager
+      SILE.input.fontmanager = opts.fontmanager
    end
    if opts.makedeps then
       SILE.makeDeps = require("core.makedeps")
diff --git a/core/fontmanager.lua b/core/fontmanager.lua
index 44792dc97..b541e6dd4 100644
--- a/core/fontmanager.lua
+++ b/core/fontmanager.lua
@@ -1,20 +1,36 @@
 local fontManager = {}
+
 fontManager.fontconfig = require("justenoughfontconfig")
-pcall(function ()
-   fontManager.macfonts = require("macfonts")
-end)
+
+local has_macfonts, macfonts = pcall(require, "macfonts")
+if has_macfonts and macfonts then
+   fontManager.macfonts = macfonts
+end
+
+local function create_macfonts_fallback (self)
+   return function (...)
+      SU.debug("fonts", "Checking via macfonts")
+      local status, result = pcall(self.macfonts._face, ...)
+      if status and result and result.filename then
+         SU.debug("fonts", "Found, returning result")
+         return result
+      else
+         SU.debug("fonts", "Not found, trying fontconfig instead")
+         return self.fontconfig._face(...)
+      end
+   end
+end
 
 fontManager.face = function (self, ...)
-   local manager
-   if SILE.forceFontManager then
-      manager = self[SILE.forceFontManager]
+   local face
+   if SILE.input.fontmanager then
+      face = self[SILE.input.fontmanager]._face
+   elseif has_macfonts then
+      face = create_macfonts_fallback(self)
    else
-      manager = self.macfonts and self.macfonts or self.fontconfig
-   end
-   if not manager then
-      SU.error("Failed to load any working font manager")
+      face = self.fontconfig._face
    end
-   return manager._face(...)
+   return face(...)
 end
 
 return fontManager
diff --git a/core/pathsetup.lua.in b/core/pathsetup.lua.in
index d7556f58d..3ad11b287 100644
--- a/core/pathsetup.lua.in
+++ b/core/pathsetup.lua.in
@@ -43,6 +43,9 @@ end
 -- Prepend paths specifically for C modules.
 local function prependCPath (path)
    package.cpath = prepend_and_dedup(path .. "/?.@SHARED_LIB_EXT@", package.cpath)
+   if "@SHARED_LIB_EXT@" ~= "so" then
+      package.cpath = prepend_and_dedup(path .. "/?.so", package.cpath)
+   end
 end
 
 -- Take a given path and iterate over permutations of paths that LuaRocks might have installed a rock to that are
diff --git a/core/sile.lua b/core/sile.lua
index 1192baf6a..4881b16f4 100644
--- a/core/sile.lua
+++ b/core/sile.lua
@@ -205,22 +205,26 @@ end
 --
 -- Does not move on to processing input document(s).
 function SILE.init ()
-   if not SILE.backend then
-      SILE.backend = "libtexpdf"
+   if SILE.backend then
+      SU.deprecated("SILE.backend", "SILE.input.backend", "0.15.7", "0.17.0")
+      SILE.input.backend = SILE.backend
    end
-   if SILE.backend == "libtexpdf" then
+   if not SILE.input.backend then
+      SILE.input.backend = "libtexpdf"
+   end
+   if SILE.input.backend == "libtexpdf" then
       SILE.shaper = SILE.shapers.harfbuzz()
       SILE.outputter = SILE.outputters.libtexpdf()
-   elseif SILE.backend == "cairo" then
+   elseif SILE.input.backend == "cairo" then
       SILE.shaper = SILE.shapers.pango()
       SILE.outputter = SILE.outputters.cairo()
-   elseif SILE.backend == "debug" then
+   elseif SILE.input.backend == "debug" then
       SILE.shaper = SILE.shapers.harfbuzz()
       SILE.outputter = SILE.outputters.debug()
-   elseif SILE.backend == "text" then
+   elseif SILE.input.backend == "text" then
       SILE.shaper = SILE.shapers.harfbuzz()
       SILE.outputter = SILE.outputters.text()
-   elseif SILE.backend == "dummy" then
+   elseif SILE.input.backend == "dummy" then
       SILE.shaper = SILE.shapers.harfbuzz()
       SILE.outputter = SILE.outputters.dummy()
    end
diff --git a/inputters/lua_spec.lua b/inputters/lua_spec.lua
index 2b9f2892d..588e512ff 100644
--- a/inputters/lua_spec.lua
+++ b/inputters/lua_spec.lua
@@ -1,5 +1,5 @@
 SILE = require("core.sile")
-SILE.backend = "dummy"
+SILE.input.backend = "dummy"
 SILE.init()
 SILE.utilities.error = error
 
diff --git a/inputters/sil_spec.lua b/inputters/sil_spec.lua
index 78fdf4785..69290a0f9 100644
--- a/inputters/sil_spec.lua
+++ b/inputters/sil_spec.lua
@@ -1,5 +1,5 @@
 SILE = require("core.sile")
-SILE.backend = "dummy"
+SILE.input.backend = "dummy"
 SILE.init()
 SILE.utilities.error = error
 
diff --git a/inputters/xml_spec.lua b/inputters/xml_spec.lua
index 3b2077e41..d983251a2 100644
--- a/inputters/xml_spec.lua
+++ b/inputters/xml_spec.lua
@@ -1,5 +1,5 @@
 SILE = require("core.sile")
-SILE.backend = "dummy"
+SILE.input.backend = "dummy"
 SILE.init()
 SILE.utilities.error = error
 
diff --git a/packages/counters/counters_spec.lua b/packages/counters/counters_spec.lua
index 74e53d65a..14d760829 100644
--- a/packages/counters/counters_spec.lua
+++ b/packages/counters/counters_spec.lua
@@ -1,5 +1,5 @@
 SILE = require("core.sile")
-SILE.backend = "dummy"
+SILE.input.backend = "dummy"
 SILE.init()
 SILE.utilities.error = error
 
diff --git a/rusile/Cargo.toml b/rusile/Cargo.toml
index dbe411618..3f108ec59 100644
--- a/rusile/Cargo.toml
+++ b/rusile/Cargo.toml
@@ -9,6 +9,7 @@ authors.workspace = true
 homepage.workspace = true
 repository.workspace = true
 license.workspace = true
+build = "../build-aux/module.rs"
 
 [lib]
 crate-type = ["rlib", "cdylib", "staticlib"]
diff --git a/spec/complex_frame_spec.lua b/spec/complex_frame_spec.lua
index b20db4af2..7bc2c00ac 100644
--- a/spec/complex_frame_spec.lua
+++ b/spec/complex_frame_spec.lua
@@ -1,6 +1,6 @@
 SILE = require("core.sile")
 
-SILE.backend = "dummy"
+SILE.input.backend = "dummy"
 SILE.init()
 
 local base = require("classes.base")
diff --git a/spec/fontmanager_spec.lua b/spec/fontmanager_spec.lua
new file mode 100644
index 000000000..e6b822afb
--- /dev/null
+++ b/spec/fontmanager_spec.lua
@@ -0,0 +1,54 @@
+SILE = require("core.sile")
+SILE.input.backend = "debug"
+SILE.init()
+
+-- These tests depend on loading specific fonts from our test fixtures. Running
+-- plain `busted` is sometimes useful (e.g. for IDEs) but will not support this
+-- test because fontconfig hasn't been preloaded with the font paths it would
+-- need. If that's the case, just skip even defining these tests and call it
+-- good. To test a complete set of tests use `make busted`.
+local fcf = os.getenv("FONTCONFIG_FILE")
+if not fcf then
+   return
+end
+
+describe("The fontconfig manager", function ()
+   SILE.input.fontmanager = "fontconfig"
+
+   it("should load a font", function ()
+      local family = "Libertinus Serif"
+      local face = SILE.shaper.getFace({ family = family })
+      assert.is.equal(family, face.family)
+   end)
+
+   it("should fallback when it can't find", function ()
+      local family = "Yesteryear Imagination"
+      local face
+      assert.has_no.errors(function ()
+         face = SILE.shaper.getFace({ family = family })
+      end)
+      assert.is_not.equal(family, face.family)
+   end)
+end)
+
+describe("The macfonts manager", function ()
+
+   if not SILE.fontManager.macfonts then
+      return
+   end
+
+   it("should load a font", function ()
+      local family = "Libertinus Serif"
+      local face = SILE.shaper.getFace({ family = family })
+      assert.is.equal(family, face.family)
+   end)
+
+   it("should fallback to fontconfig when it fails", function ()
+      local family = "Yesteryear Imagination"
+      local face
+      assert.has_no.errors(function ()
+         face = SILE.shaper.getFace({ family = family })
+      end)
+      assert.is_not.equal(family, face.family)
+   end)
+end)
diff --git a/spec/hyphenator_spec.lua b/spec/hyphenator_spec.lua
index 5daa07831..4363dc2d0 100644
--- a/spec/hyphenator_spec.lua
+++ b/spec/hyphenator_spec.lua
@@ -1,6 +1,6 @@
 SILE = require("core.sile")
 -- Using French below requires the shaper to be initialized
-SILE.backend = "debug"
+SILE.input.backend = "debug"
 SILE.init()
 
 describe("Hyphenation module", function ()
diff --git a/spec/opentype_spec.lua b/spec/opentype_spec.lua
index 82c4342ed..fcf183d5e 100644
--- a/spec/opentype_spec.lua
+++ b/spec/opentype_spec.lua
@@ -1,6 +1,6 @@
 SILE = require("core.sile")
-SILE.backend = "debug"
-SILE.forceFontManager = "fontconfig"
+SILE.input.backend = "debug"
+SILE.input.fontmanager = "fontconfig"
 SILE.init()
 
 -- These tests depend on loading specific fonts from our test fixtures. Running
diff --git a/spec/shaper_spec.lua b/spec/shaper_spec.lua
index 3a548a2db..72f600f9e 100644
--- a/spec/shaper_spec.lua
+++ b/spec/shaper_spec.lua
@@ -1,5 +1,5 @@
 SILE = require("core.sile")
-SILE.backend = "debug"
+SILE.input.backend = "debug"
 SILE.init()
 
 describe("SILE.shapers.base", function ()
diff --git a/src/lib.rs b/src/lib.rs
index 00cf621be..6bf4b8195 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -133,10 +133,10 @@ pub fn run(
         sile_input.set("evaluateAfters", expressions)?;
     }
     if let Some(backend) = backend {
-        sile.set("backend", backend)?;
+        sile_input.set("backend", backend)?;
     }
     if let Some(fontmanager) = fontmanager {
-        sile.set("fontmanager", fontmanager)?;
+        sile_input.set("fontmanager", fontmanager)?;
     }
     if let Some(class) = class {
         sile_input.set("class", class)?;