diff --git a/.gitignore b/.gitignore
index 7cb3dfee5f..25412b5335 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,7 +8,7 @@ share/
 include/
 obj/
 cpp/
-.pre-build
+pre-build.log
 src/vg_git_version.hpp
 src/vg_environment_version.hpp
 *.o
diff --git a/.gitmodules b/.gitmodules
index 1bb80d2346..c15f27aa26 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -22,9 +22,6 @@
 [submodule "sdsl-lite"]
 	path = deps/sdsl-lite
     url = https://github.com/vgteam/sdsl-lite.git
-[submodule "deps/libVCFH"]
-	path = deps/libVCFH
-	url = https://github.com/edawson/libVCFH.git
 [submodule "deps/sparsehash"]
 	path = deps/sparsehash
 	url = https://github.com/sparsehash/sparsehash.git
diff --git a/Dockerfile b/Dockerfile
index b068542a67..e1e3e8402c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,6 +3,9 @@
 # Use Google's non-rate-limited mirror of Docker Hub to get our base image.
 # This helps automated Quay builds because Quay hasn't built a caching system
 # and exposes pull rate limits to users.
+# We need to use Ubuntu 22.04 because 24.04 and later suffer from
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104888 and don't package a
+# libcairo.a at all.
 FROM mirror.gcr.io/library/ubuntu:22.04 AS base
 MAINTAINER vgteam
 
@@ -60,18 +63,20 @@ RUN if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then sed -i s/m
 # Clear any CMake caches in case we are building from someone's checkout
 RUN find . -name CMakeCache.txt | xargs rm -f
 # Build the dependencies
+COPY pre-build.sh /vg/pre-build.sh
 COPY Makefile /vg/Makefile
-RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" CFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) deps
+# Turn off user-defined conversion warning until https://github.com/greg7mdp/sparsepp/issues/98 can be fixed
+RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi) -Wno-cast-user-defined" CFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) deps
 
 # Bring in the sources, which we need in order to build.
 COPY src /vg/src
 
 # Build all the object files for vg, but don't link.
 # Also pass the arch here
-RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) objs
+RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi) -Wno-cast-user-defined" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) objs
 
 # Do the final build and link, knowing the version. Trim down the resulting binary but make sure to include enough debug info for profiling.
-RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi)" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) static && strip -d bin/vg
+RUN CXXFLAGS="$(if [ -z "${TARGETARCH}" ] || [ "${TARGETARCH}" = "amd64" ] ; then echo " -march=nehalem "; fi) -Wno-cast-user-defined" make -j $((THREADS < $(nproc) ? THREADS : $(nproc))) static && strip -d bin/vg
 
 # Ship the scripts
 COPY scripts /vg/scripts
@@ -124,7 +129,7 @@ RUN ls -lah /vg && \
     fontconfig-config \
     awscli \
     binutils \
-    libpython2.7 \
+    python3 \
     libperl-dev \
     libelf1 \
     libdw1 \
diff --git a/Makefile b/Makefile
index 6506208d58..9838fde9fd 100644
--- a/Makefile
+++ b/Makefile
@@ -74,7 +74,7 @@ INCLUDE_FLAGS :=-I$(CWD)/$(INC_DIR) -I. -I$(CWD)/$(SRC_DIR) -I$(CWD)/$(UNITTEST_
 # These need to come before library search paths from LDFLAGS or we won't
 # prefer linking vg-installed dependencies over system ones.
 LD_LIB_DIR_FLAGS := -L$(CWD)/$(LIB_DIR)
-LD_LIB_FLAGS := -lvcflib -lwfa2 -ltabixpp -lgssw -lssw -lsublinearLS -lpthread -lncurses -lgcsa2 -lgbwtgraph -lgbwt -lkff -ldivsufsort -ldivsufsort64 -lvcfh -lraptor2 -lpinchesandcacti -l3edgeconnected -lsonlib -lfml -lstructures -lbdsg -lxg -lsdsl -lzstd -lhandlegraph -lcrypto
+LD_LIB_FLAGS := -lvcflib -lwfa2 -ltabixpp -lgssw -lssw -lsublinearLS -lpthread -lncurses -lgcsa2 -lgbwtgraph -lgbwt -lkff -ldivsufsort -ldivsufsort64 -lraptor2 -lpinchesandcacti -l3edgeconnected -lsonlib -lfml -lstructures -lbdsg -lxg -lsdsl -lzstd -lhandlegraph -lcrypto
 # We omit Boost Program Options for now; we find it in a platform-dependent way.
 # By default it has no suffix
 BOOST_SUFFIX=""
@@ -396,7 +396,6 @@ LIB_DEPS += $(LIB_DIR)/libhts.a
 LIB_DEPS += $(LIB_DIR)/libtabixpp.a
 LIB_DEPS += $(LIB_DIR)/libvcflib.a
 LIB_DEPS += $(LIB_DIR)/libgssw.a
-LIB_DEPS += $(LIB_DIR)/libvcfh.a
 LIB_DEPS += $(LIB_DIR)/libsonlib.a
 LIB_DEPS += $(LIB_DIR)/libpinchesandcacti.a
 LIB_DEPS += $(LIB_DIR)/libraptor2.a
@@ -519,7 +518,7 @@ DEPS += $(INC_DIR)/BooPHF.h
 DEPS += $(INC_DIR)/mio/mmap.hpp
 DEPS += $(INC_DIR)/atomic_queue.h
 
-.PHONY: clean clean-tests get-deps deps lint test set-path objs static static-docker docs man .pre-build version
+.PHONY: clean clean-tests get-deps deps lint test set-path objs static static-docker docs man version
 
 # Aggregate all libvg deps, and exe deps other than libvg
 LIBVG_DEPS = $(OBJ) $(ALGORITHMS_OBJ) $(IO_OBJ) $(DEP_OBJ) $(DEPS)
@@ -569,7 +568,7 @@ get-deps:
 	sudo DEBIAN_FRONTEND=$(DEBIAN_FRONTEND) apt-get install -qq -y --no-upgrade $(shell cat Dockerfile | sed -n '/^###DEPS_BEGIN###/,$${p;/^###DEPS_END###/q}' | grep -v '^ *#' | grep -v "^RUN" | tr '\n' ' ' | tr -d '\\')
 
 # And we have submodule deps to build
-deps: $(DEPS)
+deps: $(DEPS) $(LINK_DEPS) $(PRE_LINK_DEPS)
 
 lint: $(SRC_DIR)/*.cpp $(SRC_DIR)/*.hpp $(ALGORITHMS_SRC_DIR)/*.cpp $(ALGORITHMS_SRC_DIR)/*.hpp $(SUBCOMMAND_SRC_DIR)/*.cpp $(SUBCOMMAND_SRC_DIR)/*.hpp $(UNITTEST_SRC_DIR)/*.cpp $(UNITTEST_SRC_DIR)/*.hpp $(UNITTEST_SUPPORT_SRC_DIR)/*.cpp
 	scripts/check_options.py 1>&2
@@ -722,6 +721,7 @@ $(LIB_DIR)/cleaned_old_catch:
 	+touch $(LIB_DIR)/cleaned_old_catch
 
 $(LIB_DIR)/libvgio.a: $(LIB_DIR)/libhts.a $(LIB_DIR)/libhandlegraph.a $(LIB_DIR)/pkgconfig/htslib.pc $(LIB_DIR)/cleaned_old_protobuf_v003 $(LIBVGIO_DIR)/CMakeLists.txt $(LIBVGIO_DIR)/src/*.cpp $(LIBVGIO_DIR)/include/vg/io/*.hpp $(LIBVGIO_DIR)/deps/vg.proto
+	@protoc --version >/dev/null 2>/dev/null || (echo "Error: protobuf compiler (protoc) not available!" ; exit 1)
 	+rm -f $(CWD)/$(INC_DIR)/vg.pb.h $(CWD)/$(INC_DIR)/vg/vg.pb.h
 	+rm -Rf $(CWD)/$(INC_DIR)/vg/io/
 	+export CXXFLAGS="$(CPPFLAGS) $(CXXFLAGS)" && export LDFLAGS="$(LD_LIB_DIR_FLAGS) $(LDFLAGS)" && cd $(LIBVGIO_DIR) && rm -Rf CMakeCache.txt CMakeFiles *.cmake install_manifest.txt *.pb.cc *.pb.h *.a && rm -rf build-vg && mkdir build-vg && cd build-vg && PKG_CONFIG_PATH=$(CWD)/$(LIB_DIR)/pkgconfig:$(PKG_CONFIG_PATH) cmake -DCMAKE_C_COMPILER="$(CC)" -DCMAKE_CXX_COMPILER="$(CXX)" -DCMAKE_CXX_STANDARD=$(CXX_STANDARD) -DCMAKE_VERBOSE_MAKEFILE=ON -DCMAKE_PREFIX_PATH="/usr;$(OMP_PREFIXES)" -DCMAKE_INSTALL_PREFIX=$(CWD) -DCMAKE_INSTALL_LIBDIR=lib -DUSE_INSTALLED_LIBHANDLEGRAPH_ONLY=ON .. $(FILTER) && $(MAKE) clean && VERBOSE=1 $(MAKE) $(FILTER) && $(MAKE) install
@@ -825,10 +825,6 @@ $(INC_DIR)/sparsehash/sparse_hash_map: $(wildcard $(SPARSEHASH_DIR)/**/*.cc) $(w
 $(INC_DIR)/sparsepp/spp.h: $(wildcard $(SPARSEPP_DIR)/sparsepp/*.h)
 	+cp -r $(SPARSEPP_DIR)/sparsepp $(INC_DIR)/
 
-#$(INC_DIR)/Variant.h
-$(LIB_DIR)/libvcfh.a: $(DEP_DIR)/libVCFH/*.cpp $(DEP_DIR)/libVCFH/*.hpp
-	+cd $(DEP_DIR)/libVCFH && $(MAKE) $(FILTER) && cp libvcfh.a $(CWD)/$(LIB_DIR)/ && cp vcfheader.hpp $(CWD)/$(INC_DIR)/
-
 $(LIB_DIR)/libsonlib.a: $(CWD)/$(DEP_DIR)/sonLib/C/inc/*.h $(CWD)/$(DEP_DIR)/sonLib/C/impl/*.c
 	+cd $(DEP_DIR)/sonLib && $(MAKE) clean && kyotoTycoonLib="" CFLAGS="-fPIC $(CFLAGS)" CXXFLAGS="-fPIC $(CXXFLAGS)" $(MAKE) $(FILTER) && cp lib/sonLib.a $(CWD)/$(LIB_DIR)/libsonlib.a && mkdir -p $(CWD)/$(INC_DIR)/sonLib && cp lib/*.h $(CWD)/$(INC_DIR)/sonLib
 
@@ -934,6 +930,9 @@ $(LIB_DIR)/libxg.a: $(XG_DIR)/src/*.hpp $(XG_DIR)/src/*.cpp $(INC_DIR)/mmmultima
 	+$(CXX) $(INCLUDE_FLAGS) $(CXXFLAGS) $(CPPFLAGS) -fPIC -DNO_GFAKLUGE -c -o $(XG_DIR)/xg.o $(XG_DIR)/src/xg.cpp $(FILTER)
 	+ar rs $@ $(XG_DIR)/xg.o
 
+# All this version header generation stuff needs to work even if SRC_DIR hasn't been copied into the container yet.
+$(shell mkdir -p $(SRC_DIR))
+
 # Auto-git-versioning
 
 # Can be overridden from the environment to supply a version if none is on disk.
@@ -957,7 +956,7 @@ ifeq ($(shell if [ -d .git ]; then echo present; else echo absent; fi),present)
 else
     # Just use the version file we have, if any.
     $(info Do not check Git)
-    $(shell if [ ! -e $(SRC_DIR)/vg_git_version.hpp] ; then echo "#define VG_GIT_VERSION \"$(VG_GIT_VERSION)\"" > $(SRC_DIR)/vg_git_version.hpp ; fi)
+    $(shell if [ ! -e $(SRC_DIR)/vg_git_version.hpp ] ; then echo "#define VG_GIT_VERSION \"$(VG_GIT_VERSION)\"" > $(SRC_DIR)/vg_git_version.hpp ; fi)
 endif
 
 
@@ -968,7 +967,7 @@ version:
 # Build an environment version file.
 # If it's not the same as the old one, replace the old one.
 # If it is the same, do nothing and don't rebuild dependent targets.
-# Clean old path
+# Clean old path.
 $(shell rm -f $(INC_DIR)/vg_environment_version.hpp)
 $(shell echo "#define VG_COMPILER_VERSION \"$(shell $(CXX) --version 2>/dev/null | head -n 1)\"" > $(SRC_DIR)/vg_environment_version.hpp.tmp)
 $(shell echo "#define VG_OS \"$(shell uname)\"" >> $(SRC_DIR)/vg_environment_version.hpp.tmp)
@@ -1055,54 +1054,36 @@ test/%.d: ;
 ## VG source code compilation ends here
 ####################################
 
-
-# Make directories before quitting target due to missing protoc.
-# If we run the rest of the build without these, lib and include can become files.
-# TODO: quitting if no protoc doesn't reliably stop the build.
-.pre-build:
-	@if [ ! -d $(BIN_DIR) ]; then mkdir -p $(BIN_DIR); fi
-	@if [ ! -d $(UNITTEST_BIN_DIR) ]; then mkdir -p $(UNITTEST_BIN_DIR); fi
-	@if [ ! -d $(LIB_DIR) ]; then mkdir -p $(LIB_DIR); fi
-	@if [ ! -d $(OBJ_DIR) ]; then mkdir -p $(OBJ_DIR); fi
-	@if [ ! -d $(SHARED_OBJ_DIR) ]; then mkdir -p $(SHARED_OBJ_DIR); fi
-	@if [ ! -d $(ALGORITHMS_OBJ_DIR) ]; then mkdir -p $(ALGORITHMS_OBJ_DIR); fi
-	@if [ ! -d $(ALGORITHMS_SHARED_OBJ_DIR) ]; then mkdir -p $(ALGORITHMS_SHARED_OBJ_DIR); fi
-	@if [ ! -d $(CONFIG_OBJ_DIR) ]; then mkdir -p $(CONFIG_OBJ_DIR); fi
-	@if [ ! -d $(IO_OBJ_DIR) ]; then mkdir -p $(IO_OBJ_DIR); fi
-	@if [ ! -d $(IO_SHARED_OBJ_DIR) ]; then mkdir -p $(IO_SHARED_OBJ_DIR); fi
-	@if [ ! -d $(SUBCOMMAND_OBJ_DIR) ]; then mkdir -p $(SUBCOMMAND_OBJ_DIR); fi
-	@if [ ! -d $(UNITTEST_OBJ_DIR) ]; then mkdir -p $(UNITTEST_OBJ_DIR); fi
-	@if [ ! -d $(UNITTEST_SUPPORT_OBJ_DIR) ]; then mkdir -p $(UNITTEST_SUPPORT_OBJ_DIR); fi
-	@if [ ! -d $(INC_DIR) ]; then mkdir -p $(INC_DIR); fi
-	@protoc --version >/dev/null 2>/dev/null || (echo "Error: protobuf compiler (protoc) not available!" ; exit 1)
-	@if [ -e $(INC_DIR)/vg/vg.pb.h ] ; then \
-		HEADER_VER=$$(cat $(INC_DIR)/vg/vg.pb.h | grep GOOGLE_PROTOBUF_VERSION | sed 's/[^0-9]*\([0-9]*\)[^0-9]*/\1/' | head -n1); \
-		WORKDIR=$$(pwd); \
-		TESTDIR=$$(mktemp -d); \
-		echo 'syntax = "proto3";' > $${TESTDIR}/empty.proto; \
-		protoc $${TESTDIR}/empty.proto --proto_path=$${TESTDIR} --cpp_out=$${TESTDIR}; \
-		PROTOC_VER=$$(cat $${TESTDIR}/empty.pb.h | grep GOOGLE_PROTOBUF_VERSION | sed 's/[^0-9]*\([0-9]*\)[^0-9]*/\1/' | head -n1); \
-		if [ "$${HEADER_VER}" != "$${PROTOC_VER}" ] ; then \
-			echo "Protobuf version has changed!"; \
-			echo "Headers are for $${HEADER_VER} but we make headers for $${PROTOC_VER}"; \
-			echo "Need to rebuild libvgio"; \
-			rm -f $(LIB_DIR)/libvgio.a; \
-			rm -f $(INC_DIR)/vg/vg.pb.h; \
-		fi; \
-		rm $${TESTDIR}/empty.proto $${TESTDIR}/empty.pb.h $${TESTDIR}/empty.pb.cc; \
-		rmdir $${TESTDIR}; \
-	fi;
-
-# A note about Protobuf:
-# We have a lot of logic here to make sure that the protoc we have henerates headers with exactly the same
-# version requirements as the headers we already have.
-# If not, we regenerate them.
-# Doesn't handle Protobuf 3.12.3 weirdness; just make clean if you change flavors of Protobuf 3.12.3.
-	
-	
-	
-# run .pre-build before we make anything at all.
--include .pre-build
+# Make all the directories we need.
+# If these don't exist, they can become files (somehow) when we run the rest of
+# the build.
+# We used to run a target to do this but since GNU Make 4.4 we can't easily run
+# a target at startup by `-include`-ing a .PHONY target so we need to do it at
+# top-level with shell calls. See <https://stackoverflow.com/a/76870264>
+$(shell if [ ! -d $(BIN_DIR) ]; then mkdir -p $(BIN_DIR); fi)
+$(shell if [ ! -d $(UNITTEST_BIN_DIR) ]; then mkdir -p $(UNITTEST_BIN_DIR); fi)
+$(shell if [ ! -d $(LIB_DIR) ]; then mkdir -p $(LIB_DIR); fi)
+$(shell if [ ! -d $(OBJ_DIR) ]; then mkdir -p $(OBJ_DIR); fi)
+$(shell if [ ! -d $(SHARED_OBJ_DIR) ]; then mkdir -p $(SHARED_OBJ_DIR); fi)
+$(shell if [ ! -d $(ALGORITHMS_OBJ_DIR) ]; then mkdir -p $(ALGORITHMS_OBJ_DIR); fi)
+$(shell if [ ! -d $(ALGORITHMS_SHARED_OBJ_DIR) ]; then mkdir -p $(ALGORITHMS_SHARED_OBJ_DIR); fi)
+$(shell if [ ! -d $(CONFIG_OBJ_DIR) ]; then mkdir -p $(CONFIG_OBJ_DIR); fi)
+$(shell if [ ! -d $(IO_OBJ_DIR) ]; then mkdir -p $(IO_OBJ_DIR); fi)
+$(shell if [ ! -d $(IO_SHARED_OBJ_DIR) ]; then mkdir -p $(IO_SHARED_OBJ_DIR); fi)
+$(shell if [ ! -d $(SUBCOMMAND_OBJ_DIR) ]; then mkdir -p $(SUBCOMMAND_OBJ_DIR); fi)
+$(shell if [ ! -d $(UNITTEST_OBJ_DIR) ]; then mkdir -p $(UNITTEST_OBJ_DIR); fi)
+$(shell if [ ! -d $(UNITTEST_SUPPORT_OBJ_DIR) ]; then mkdir -p $(UNITTEST_SUPPORT_OBJ_DIR); fi)
+$(shell if [ ! -d $(INC_DIR) ]; then mkdir -p $(INC_DIR); fi)
+
+# run pre-build.sh before we make anything at all.
+# Make really doesn't want to depend on this succeeding, but we need it to.
+# See <https://stackoverflow.com/a/225626>.
+# Make sure to run right now.
+PREBUILD_RESULT:=$(shell ./pre-build.sh >pre-build.log 2>&1 ; echo $$?)
+ifneq ($(PREBUILD_RESULT), 0)
+    $(info $(shell cat pre-build.log))
+    $(error Pre-build script failed)
+endif
 
 # for rebuilding just vg
 clean-vg:
@@ -1146,7 +1127,6 @@ clean: clean-vcflib
 	cd $(DEP_DIR) && cd ssw && cd src && $(MAKE) clean
 	cd $(DEP_DIR) && cd progress_bar && $(MAKE) clean
 	cd $(DEP_DIR) && cd sdsl-lite && ./uninstall.sh || true
-	cd $(DEP_DIR) && cd libVCFH && $(MAKE) clean
 	cd $(DEP_DIR) && cd vcflib && $(MAKE) clean
 	cd $(DEP_DIR) && cd sha1 && $(MAKE) clean
 	cd $(DEP_DIR) && cd structures && $(MAKE) clean
@@ -1161,5 +1141,4 @@ clean: clean-vcflib
 
 clean-vcflib:
 	cd $(DEP_DIR) && cd vcflib && $(MAKE) clean
-	rm -f $(LIB_DIR)/libvcfh.a
 	cd $(INC_DIR) && rm -f BedReader.h convert.h join.h mt19937ar.h split.h Variant.h vec128int.h veclib_types.h
diff --git a/deps/elfutils b/deps/elfutils
index 983e86fd89..302252356d 160000
--- a/deps/elfutils
+++ b/deps/elfutils
@@ -1 +1 @@
-Subproject commit 983e86fd89e8bf02f2d27ba5dce5bf078af4ceda
+Subproject commit 302252356da5475670ac5b10dadd091c59689425
diff --git a/deps/libVCFH b/deps/libVCFH
deleted file mode 160000
index 615a06b5de..0000000000
--- a/deps/libVCFH
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 615a06b5de21f59294d7d806e9f505162ae8c2c1
diff --git a/deps/libbdsg b/deps/libbdsg
index 73e74c223e..5429995457 160000
--- a/deps/libbdsg
+++ b/deps/libbdsg
@@ -1 +1 @@
-Subproject commit 73e74c223ed16c6b0db2c378f285819c5a3499e0
+Subproject commit 54299954575a980c8506624e52e1593333a2a6d1
diff --git a/deps/sparsehash b/deps/sparsehash
index a61a6ba7ad..1dffea3d91 160000
--- a/deps/sparsehash
+++ b/deps/sparsehash
@@ -1 +1 @@
-Subproject commit a61a6ba7adbc4e3a7545843a72c530bf35604dae
+Subproject commit 1dffea3d917445d70d33d0c7492919fc4408fe5c
diff --git a/deps/structures b/deps/structures
index d9e184da87..d283203c3b 160000
--- a/deps/structures
+++ b/deps/structures
@@ -1 +1 @@
-Subproject commit d9e184da87492535c5e69d60706ee02a7eb2e82e
+Subproject commit d283203c3b7021dc83352318429be5aad1995510
diff --git a/pre-build.sh b/pre-build.sh
new file mode 100755
index 0000000000..9f3c474856
--- /dev/null
+++ b/pre-build.sh
@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# pre-build.sh: setup commands to run before building anything.
+# Invoked by the Makefile automatically.
+# If this script fails, the build will fail.
+set -e
+
+# We don't want to put dependency checks here because we run before `make
+# get-deps` can do any dep-getting.
+
+if which protoc >/dev/null 2>&1 && [ -e include/vg/vg.pb.h ] ; then
+    HEADER_VER=$(cat include/vg/vg.pb.h | grep GOOGLE_PROTOBUF_VERSION | sed 's/[^0-9]*\([0-9]*\)[^0-9]*/\1/' | head -n1); \
+    WORKDIR=$(pwd); \
+    TESTDIR=$(mktemp -d); \
+    echo 'syntax = "proto3";' > ${TESTDIR}/empty.proto; \
+    protoc ${TESTDIR}/empty.proto --proto_path=${TESTDIR} --cpp_out=${TESTDIR}; \
+    PROTOC_VER=$(cat ${TESTDIR}/empty.pb.h | grep GOOGLE_PROTOBUF_VERSION | sed 's/[^0-9]*\([0-9]*\)[^0-9]*/\1/' | head -n1); \
+    if [ "${HEADER_VER}" != "${PROTOC_VER}" ] ; then \
+        echo "Protobuf version has changed!"; \
+        echo "Headers are for ${HEADER_VER} but we make headers for ${PROTOC_VER}"; \
+        echo "Need to rebuild libvgio"; \
+        rm -f lib/libvgio.a; \
+        rm -f include/vg/vg.pb.h; \
+    fi; \
+    rm ${TESTDIR}/empty.proto ${TESTDIR}/empty.pb.h ${TESTDIR}/empty.pb.cc; \
+    rmdir ${TESTDIR}; \
+fi;
+
+# A note about Protobuf:
+# We have a lot of logic here to make sure that the protoc we have generates headers with exactly the same
+# version requirements as the headers we already have.
+# If not, we regenerate them.
+# Doesn't handle Protobuf 3.12.3 weirdness; just make clean if you change flavors of Protobuf 3.12.3.