diff --git a/.github/workflows/c-cpp.yml b/.github/workflows/c-cpp.yml
index 43e1489e..f0a71d24 100644
--- a/.github/workflows/c-cpp.yml
+++ b/.github/workflows/c-cpp.yml
@@ -17,7 +17,7 @@ jobs:
       - name: Set up build environment (macOS)
         run: |
           brew update
-          brew install check
+          brew install check pkg-config
         if: runner.os == 'macOS'
       - uses: actions/checkout@v6
       - name: Build
diff --git a/.github/workflows/cross-platform-actions.yml b/.github/workflows/cross-platform-actions.yml
index 8864bb74..cf86e6b1 100644
--- a/.github/workflows/cross-platform-actions.yml
+++ b/.github/workflows/cross-platform-actions.yml
@@ -14,33 +14,34 @@ jobs:
             version: '6.4.2'
             pkginstall: |
               sudo pkg update
-              sudo pkg install -y check gmake
+              sudo pkg install -y check gmake pkgconf
           - operating_system: freebsd
             version: '15.0'
             pkginstall: |
               sudo pkg update
-              sudo pkg install -y check gmake
+              sudo pkg install -y check gmake pkgconf
           - operating_system: haiku
             version: 'r1beta5'
             pkginstall: |
               pkgman update -y
-              pkgman install -y check_devel
+              pkgman install -y check_devel pkgconfig
           - operating_system: midnightbsd
             version: '4.0.4'
             pkginstall: |
               sudo mport upgrade
-              sudo mport install check gmake || true
+              sudo mport install check gmake pkgconf || true
           - operating_system: netbsd
             version: '10.1'
             pkginstall: |
               sudo pkgin update
-              sudo pkgin -y install check clang gmake
+              sudo pkgin -y install check clang gmake pkg-config
           - operating_system: omnios
             version: 'r151058'
             pkginstall: |
               sudo pkg update || true
-              sudo pkg install build-essential
+              sudo pkg install build-essential pkg-config
               sudo ln -s /usr/bin/gcc /usr/bin/cc
+              # From https://pkgsrc.smartos.org/install-on-illumos/
               curl -O https://pkgsrc.smartos.org/packages/SmartOS/bootstrap/bootstrap-trunk-x86_64-20240116.tar.gz
               sudo tar -zxpf bootstrap-trunk-x86_64-*.tar.gz -C /
               sudo /opt/local/bin/pkgin -y update
@@ -49,7 +50,7 @@ jobs:
             version: '7.9'
             pkginstall: |
               sudo pkg_add -u
-              sudo pkg_add check gmake
+              sudo pkg_add check gmake pkg-config
         exclude:
           - operating_system: dragonflybsd
             architecture: arm64
@@ -78,6 +79,9 @@ jobs:
           if [ "${{ matrix.operating_system }}" != "haiku" ]; then
             export MAKE=gmake
           fi
+          if [ "${{ matrix.operating_system }}" = "omnios" ]; then
+            export PKG_CONFIG_PATH=/opt/local/lib/pkgconfig
+          fi
           ${MAKE:-make} CC=cc
           ${MAKE:-make} clean
           ${MAKE:-make} CC=cc units UNITS=1
diff --git a/Makefile b/Makefile
index c0bdf0a0..d3df9ce5 100644
--- a/Makefile
+++ b/Makefile
@@ -15,27 +15,14 @@ RANLIB:=$(CROSS_COMPILE)ranlib
 SIZE:=$(CROSS_COMPILE)size
 STRIP_BIN:=$(CROSS_COMPILE)strip
 TEST_LDFLAGS=-pthread $(PREFIX)/modules/*.o $(PREFIX)/lib/*.o -lvdeplug
-UNIT_LDFLAGS=-lcheck -lm -pthread
-UNIT_CFLAGS= $(CFLAGS) -Wno-missing-braces -Wno-format-extra-args
 
-ifeq ($(OS),Darwin)
-	BREW_PREFIX_CHECK:=$(shell brew --prefix check)
-	UNIT_CFLAGS+=-I$(BREW_PREFIX_CHECK)/include
-	UNIT_LDFLAGS+=-L$(BREW_PREFIX_CHECK)/lib
-else ifneq ($(filter $(OS),DragonFly FreeBSD MidnightBSD OpenBSD),)
-	UNIT_CFLAGS+=-I/usr/local/include
-	UNIT_LDFLAGS+=-L/usr/local/lib
-else ifeq ($(OS),Haiku)
-	UNIT_CFLAGS+=-I/system/develop/headers
-	UNIT_LDFLAGS+=-L/system/lib -lnetwork
-else ifeq ($(OS),NetBSD)
-	UNIT_CFLAGS+=-I/usr/pkg/include
-	UNIT_LDFLAGS+=-L/usr/pkg/lib -Wl,-R/usr/pkg/lib
+PKG_CONFIG:=$(CROSS_COMPILE)pkg-config
+UNIT_CFLAGS=$(CFLAGS) -Wno-missing-braces -Wno-format-extra-args $(shell $(PKG_CONFIG) --cflags check)
+UNIT_LDFLAGS=$(shell $(PKG_CONFIG) --libs check)
+ifeq ($(OS),Haiku)
+	UNIT_LDFLAGS+=-lnetwork
 else ifeq ($(OS),SunOS)
-	UNIT_CFLAGS+=-I/opt/local/include
-	UNIT_LDFLAGS+=-L/opt/local/lib -Wl,-R/opt/local/lib -lsocket
-else ifeq ($(OS),Linux)
-	UNIT_LDFLAGS+=-lsubunit
+	UNIT_LDFLAGS+=-lsocket
 endif
 
 LIBNAME:="libpicotcp.a"