diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 504d0c6..ffac7e0 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -50,7 +50,7 @@ GR_OSMOSDR_APPEND_LIBS(
 if(GNURADIO_IQBALANCE_FOUND)
     message(STATUS "Will build with gnuradio iqbalance support.")
     add_definitions(-DHAVE_IQBALANCE=1)
-    include_directories(APPEND ${GNURADIO_IQBALANCE_INCLUDE_DIRS})
+    include_directories(${GNURADIO_IQBALANCE_INCLUDE_DIRS})
     GR_OSMOSDR_APPEND_LIBS(${GNURADIO_IQBALANCE_LIBRARIES})
 endif()
 
diff --git a/lib/fcd/CMakeLists.txt b/lib/fcd/CMakeLists.txt
index 32630fc..dbcb5e7 100644
--- a/lib/fcd/CMakeLists.txt
+++ b/lib/fcd/CMakeLists.txt
@@ -21,7 +21,7 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND
+include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${GNURADIO_FCD_INCLUDE_DIRS}
 )
diff --git a/lib/file/CMakeLists.txt b/lib/file/CMakeLists.txt
index 919b1c1..0ef8e43 100644
--- a/lib/file/CMakeLists.txt
+++ b/lib/file/CMakeLists.txt
@@ -21,7 +21,9 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND ${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
 
 set(file_srcs
     ${CMAKE_CURRENT_SOURCE_DIR}/file_source_c.cc
diff --git a/lib/miri/CMakeLists.txt b/lib/miri/CMakeLists.txt
index b9c4b02..49bd1f0 100644
--- a/lib/miri/CMakeLists.txt
+++ b/lib/miri/CMakeLists.txt
@@ -21,7 +21,7 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND
+include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${LIBMIRISDR_INCLUDE_DIR}
 )
diff --git a/lib/osmosdr/CMakeLists.txt b/lib/osmosdr/CMakeLists.txt
index 977b1ee..6474840 100644
--- a/lib/osmosdr/CMakeLists.txt
+++ b/lib/osmosdr/CMakeLists.txt
@@ -21,7 +21,7 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND
+include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${LIBOSMOSDR_INCLUDE_DIR}
 )
diff --git a/lib/rtl/CMakeLists.txt b/lib/rtl/CMakeLists.txt
index 8d1bc1d..f5464ac 100644
--- a/lib/rtl/CMakeLists.txt
+++ b/lib/rtl/CMakeLists.txt
@@ -21,7 +21,10 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND ${CMAKE_CURRENT_SOURCE_DIR} ${LIBRTLSDR_INCLUDE_DIR})
+include_directories(
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${LIBRTLSDR_INCLUDE_DIR}
+)
 
 set(rtl_srcs
     ${CMAKE_CURRENT_SOURCE_DIR}/rtl_source_c.cc
diff --git a/lib/rtl_tcp/CMakeLists.txt b/lib/rtl_tcp/CMakeLists.txt
index df2a8e8..b5bd992 100644
--- a/lib/rtl_tcp/CMakeLists.txt
+++ b/lib/rtl_tcp/CMakeLists.txt
@@ -21,7 +21,9 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND ${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
 
 set(rtl_tcp_srcs
     ${CMAKE_CURRENT_SOURCE_DIR}/rtl_tcp_source_f.cc
diff --git a/lib/uhd/CMakeLists.txt b/lib/uhd/CMakeLists.txt
index 7e29e53..2aa7e73 100644
--- a/lib/uhd/CMakeLists.txt
+++ b/lib/uhd/CMakeLists.txt
@@ -21,7 +21,7 @@
 # This file included, use CMake directory variables
 ########################################################################
 
-include_directories(APPEND
+include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${GNURADIO_UHD_INCLUDE_DIRS}
     ${UHD_INCLUDE_DIRS}