diff --git a/Makefile b/Makefile
index 4e09a71..d1bee89 100644
--- a/Makefile
+++ b/Makefile
@@ -33,11 +33,14 @@ em_flags = -std=c++17 \
 	-Wno-switch-enum \
 	-Wno-weak-vtables \
 	-Wno-missing-prototypes \
+	-Wno-unsafe-buffer-usage \
 	--bind \
 	./wrapper/hext-emscripten.cpp \
-	-I./build-dep/include \
-	./build-dep/lib/libhext.a \
-	./build-dep/lib/libgumbo.a \
+	-I./build-dep/boost/include \
+	-I./build-dep/gumbo/include \
+	-I./build-dep/libhext/include \
+	./build-dep/libhext/lib/libhext.a \
+	./build-dep/gumbo/lib/libgumbo.a \
 	-s MODULARIZE=1 \
 	-s EXPORT_NAME="loadHext" \
 	-s SINGLE_FILE=1 \
diff --git a/Makefile.boost b/Makefile.boost
index a6a80c5..d48bd90 100644
--- a/Makefile.boost
+++ b/Makefile.boost
@@ -7,7 +7,7 @@ BOOST_SHA256=2575e74ffc3ef1cd0babac2c1ee8bdb5782a0ee672b1912da40e5b4b591ca01f
 
 boost: build/boost_${BOOST_VERSION}.tar.gz \
 	build/boost_${BOOST_VERSION} \
-	build-dep/include/boost
+	build-dep/boost/include
 
 build/boost_${BOOST_VERSION}.tar.gz:
 	cd build && \
@@ -18,11 +18,17 @@ build/boost_${BOOST_VERSION}:
 	echo '${BOOST_SHA256}  boost_${BOOST_VERSION}.tar.gz' | sha256sum -c && \
 		tar xf boost_${BOOST_VERSION}.tar.gz
 
-build-dep/include/boost:
-	mkdir -p build-dep/include
-	cp -rf build/boost_${BOOST_VERSION}/boost build-dep/include/
+# Install Boost with its installer. This also creates the CMake config files, which are needed because newer
+# versions of CMake no longer ship their own FindBoost module.
+# Boost.System isn't actually needed. Boost.System is installed here, because Boost doesn't have an option to
+# only install the header-only libraries.
+build-dep/boost/include:
+	mkdir -p "${BASE}/build-dep/boost" && \
+	cd "build/boost_${BOOST_VERSION}" && \
+	./bootstrap.sh --prefix="${BASE}/build-dep/boost" --with-libraries=system && \
+	./b2 install
 
 clean:
-	rm -rf build-dep/include/boost
+	rm -rf build-dep/boost
 	rm -rf build/boost_*
 
diff --git a/Makefile.gumbo b/Makefile.gumbo
index a7e417b..273f4da 100644
--- a/Makefile.gumbo
+++ b/Makefile.gumbo
@@ -5,7 +5,7 @@ BASE=${PWD}
 all: build/v0.10.1.tar.gz build/gumbo-parser-0.10.1 \
 	build/gumbo-parser-0.10.1/configure \
 	build/gumbo-parser-0.10.1/Makefile \
-	build-dep/lib/libgumbo.a
+	build-dep/gumbo/lib/libgumbo.a
 
 build/v0.10.1.tar.gz:
 	cd build && wget https://github.com/google/gumbo-parser/archive/v0.10.1.tar.gz
@@ -21,15 +21,15 @@ build/gumbo-parser-0.10.1/configure:
 build/gumbo-parser-0.10.1/Makefile:
 	cd build/gumbo-parser-0.10.1 && \
 	emconfigure ./configure \
-		--prefix=${BASE}/build-dep \
+		--prefix=${BASE}/build-dep/gumbo \
 		--enable-static --disable-shared
 
-build-dep/lib/libgumbo.a:
+build-dep/gumbo/lib/libgumbo.a:
 	cd build/gumbo-parser-0.10.1 && \
 	emmake make install
 
 clean:
-	rm -f build-dep/lib/libgumbo.a
+	rm -rf build-dep/gumbo
 	rm -rf build/v0.10.1.tar.gz
 	rm -rf build/gumbo-parser-0.10.1
 
diff --git a/Makefile.libhext b/Makefile.libhext
index c95cc53..4e033ca 100644
--- a/Makefile.libhext
+++ b/Makefile.libhext
@@ -5,7 +5,7 @@ BASE=${PWD}
 
 all: build/v${VERSION}.tar.gz \
 	build/hext-${VERSION} \
-	build-dep/lib/libhext.a
+	build-dep/libhext/lib/libhext.a
 
 build/v${VERSION}.tar.gz:
 	cd build && \
@@ -16,25 +16,27 @@ build/hext-${VERSION}:
 	echo '${SHA256}  v${VERSION}.tar.gz' | sha256sum -c && \
 	tar xf v${VERSION}.tar.gz
 
-build-dep/lib/libhext.a:
+# CMAKE_PREFIX_PATH is ignored, unless CMAKE_FIND_ROOT_PATH_MODE_{LIBRARY,INCLUDE,PACKAGE}
+# are set to "BOTH". If unset, the emscripten toolchain module sets them to "ONLY", breaking
+# CMAKE_PREFIX_PATH.
+build-dep/libhext/lib/libhext.a:
 	cd build/hext-${VERSION}/libhext/build && \
-	emcmake cmake \
+	CMAKE_PREFIX_PATH="${BASE}/build-dep/boost:${BASE}/build-dep/gumbo" emcmake cmake \
 		-DCMAKE_AR=$(shell which emar) \
 		-DCMAKE_RANLIB=$(shell which emranlib) \
 		-DCMAKE_MAKE_PROGRAM=$(shell which emmake) \
 		-DCMAKE_C_COMPILER=$(shell which emcc) \
 		-DCMAKE_CXX_COMPILER=$(shell which em++) \
-		-DGumbo_LIBRARY=${BASE}/build-dep/lib/libgumbo.a \
-		-DGumbo_INCLUDE_DIR=${BASE}/build-dep/include \
-		-DBoost_INCLUDE_DIR=${BASE}/build-dep/include \
-		-DBoost_LIBRARY_DIR=${BASE}/build-dep/lib \
-		-DCMAKE_FIND_ROOT_PATH=${BASE}/build-dep/lib/cmake \
-		-DCMAKE_INSTALL_PREFIX=${BASE}/build-dep \
+		-DCMAKE_INSTALL_PREFIX="${BASE}/build-dep/libhext" \
+		-DCMAKE_BUILD_TYPE=Release \
+		-DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=BOTH \
+		-DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE=BOTH \
+		-DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=BOTH \
 		.. && \
 	emmake make install VERBOSE=1
 
 clean:
-	rm -f build-dep/lib/libhext.a
+	rm -rf build-dep/libhext
 	rm -rf build/v${VERSION}.tar.gz
 	rm -rf build/hext-${VERSION}