diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ef91ea7a..07f397a3e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -147,9 +147,6 @@ add_feature_info(benchmarks KATIE_BENCHMARKS "build automatic benchmarks")
 option(KATIE_UTILS "Build maintainance utilities" OFF)
 add_feature_info(utils KATIE_UTILS "build maintainance utilities")
 
-option(KATIE_ALLINONE "Build targets from single source file" OFF)
-add_feature_info(allinone KATIE_ALLINONE "build targets from single source file")
-
 option(KATIE_PCH "Build components with pre-compiled header" OFF)
 add_feature_info(pch KATIE_PCH "build components with pre-compiled header")
 
diff --git a/appveyor.yml b/appveyor.yml
index 8fe7fecde..f0d9c7a87 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -18,7 +18,7 @@ build_script:
 
     export CXXFLAGS="$CXXFLAGS -w"
 
-    cmake . -Wno-dev -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON -DKATIE_ALLINONE=ON -DKATIE_PCH=ON
+    cmake . -Wno-dev -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON -DKATIE_PCH=ON -DCMAKE_UNITY_BUILD=ON
 
     make -j $(nproc || echo 1)
 
diff --git a/cmake/modules/KatieBuildMacros.cmake b/cmake/modules/KatieBuildMacros.cmake
index 659f77f17..212448c5d 100644
--- a/cmake/modules/KatieBuildMacros.cmake
+++ b/cmake/modules/KatieBuildMacros.cmake
@@ -203,10 +203,9 @@ function(KATIE_STRING_UNWRAP INSTR OUTLST)
     endif()
 endfunction()
 
-# a macro to instruct katie_setup_target() which sources to exclude from the
-# all-in-one source file
+# a macro to instruct CMake which sources to exclude from the unity source file
 macro(KATIE_ALLINONE_EXCLUDE ARG1)
-    set_source_files_properties(${ARG1} ${ARGN} PROPERTIES ALLINONE_EXCLUDE TRUE)
+    set_source_files_properties(${ARG1} ${ARGN} PROPERTIES SKIP_UNITY_BUILD_INCLUSION TRUE)
 endmacro()
 
 # a function to create an array of source files for a target while taking into
@@ -227,6 +226,7 @@ function(KATIE_SETUP_TARGET FORTARGET)
     # this can be simpler if continue() was supported by old CMake versions
     set(resourcesdep "${CMAKE_CURRENT_BINARY_DIR}/${FORTARGET}_resources.cpp")
     katie_write_file("${resourcesdep}" "enum { CompilersWorkaroundAlaAutomoc = 1 };\n")
+    set(filteredsources)
     set(targetresources)
     set(rscpath "${CMAKE_CURRENT_BINARY_DIR}/${FORTARGET}_resources")
     include_directories("${rscpath}")
@@ -252,7 +252,8 @@ function(KATIE_SETUP_TARGET FORTARGET)
                 DEPENDS "${KATIE_RCC}"
                 OUTPUT "${rscout}"
             )
-        elseif("${rscext}" MATCHES "(.h|.hpp|.cc|.cpp)")
+        elseif("${rscext}" MATCHES "(.c|.h|.hpp|.cc|.cpp)")
+            set(filteredsources ${filteredsources} "${resource}")
             file(READ "${resource}" rsccontent)
             if("${rsccontent}" MATCHES "(Q_OBJECT|Q_OBJECT_FAKE|Q_GADGET)")
                 set(rscout "${rscpath}/moc_${rscname}${rscext}")
@@ -268,31 +269,7 @@ function(KATIE_SETUP_TARGET FORTARGET)
     endforeach()
     set_property(SOURCE "${resourcesdep}" APPEND PROPERTY OBJECT_DEPENDS "${targetresources}")
 
-    if(NOT KATIE_ALLINONE)
-        set(filteredsources)
-        foreach(srcstring ${ARGN})
-            get_filename_component(srcext "${srcstring}" EXT)
-            if(NOT "${srcext}" MATCHES "(.qrc|.ui)")
-                set(filteredsources ${filteredsources} "${srcstring}")
-            endif()
-        endforeach()
-        set(${FORTARGET}_SOURCES "${resourcesdep}" ${filteredsources} PARENT_SCOPE)
-    else()
-        set(allinonesource "${CMAKE_CURRENT_BINARY_DIR}/${FORTARGET}_allinone.cpp")
-        set(allinonedata)
-        set(excludesources)
-        foreach(srcstring ${ARGN})
-            get_filename_component(srcext "${srcstring}" EXT)
-            get_source_file_property(skip "${srcstring}" ALLINONE_EXCLUDE)
-            if(skip OR "${srcext}" STREQUAL ".c")
-                set(excludesources ${excludesources} "${srcstring}")
-            elseif(NOT "${srcext}" MATCHES "(.h|.qrc|.ui)")
-                set(allinonedata "${allinonedata}#include \"${srcstring}\"\n")
-            endif()
-        endforeach()
-        katie_write_file("${allinonesource}" "${allinonedata}")
-        set(${FORTARGET}_SOURCES ${resourcesdep} "${allinonesource}" ${excludesources} PARENT_SCOPE)
-    endif()
+    set(${FORTARGET}_SOURCES "${resourcesdep}" ${filteredsources} PARENT_SCOPE)
 endfunction()
 
 # a macro to ensure that object targets are build with PIC if the target they
diff --git a/package/archlinux/PKGBUILD b/package/archlinux/PKGBUILD
index 3262c150e..2a50357a4 100644
--- a/package/archlinux/PKGBUILD
+++ b/package/archlinux/PKGBUILD
@@ -35,8 +35,7 @@ build() {
         -DCMAKE_INSTALL_PREFIX=/usr \
         -DKATIE_LDCONF_PATH=/etc/ld.so.conf.d \
         -DKATIE_PROFILE_PATH=/etc/profile.d \
-        -DKATIE_TOOLS_SUFFIX="-katie" \
-        -DKATIE_ALLINONE=ON
+        -DKATIE_TOOLS_SUFFIX="-katie"
     make
 }
 
diff --git a/scripts/oldmake.sh b/scripts/oldmake.sh
index 7c419c1b4..e986502be 100755
--- a/scripts/oldmake.sh
+++ b/scripts/oldmake.sh
@@ -22,15 +22,7 @@ tar -xaf "$cwd/$cmake.$cmakeext"
 "$cmake/bin/cmake" ../ -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON $@
 rm -rf *
 
-tar -xaf "$cwd/$cmake.$cmakeext"
-"$cmake/bin/cmake" ../ -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON -DKATIE_ALLINONE=ON $@
-rm -rf *
-
 tar -xaf "$cwd/$cmake.$cmakeext"
 "$cmake/bin/cmake" ../ -GNinja -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON $@
 ninja -n
 rm -rf *
-
-tar -xaf "$cwd/$cmake.$cmakeext"
-"$cmake/bin/cmake" ../ -GNinja -DKATIE_TESTS=ON -DKATIE_BENCHMARKS=ON -DKATIE_UTILS=ON -DKATIE_ALLINONE=ON $@
-ninja -n