diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2039e8062..457247ed0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -719,12 +719,21 @@ endif()
 # When ENABLE_EXTERNAL_LIBRARIES is AUTO, we only build 3rd party libraries that aren't already available
 # When ENABLE_EXTERNAL_LIBRARIES is OFF, we only use prebuilt libraries
 
-if (NOT ENABLE_EXTERNAL_LIBRARIES OR (ENABLE_EXTERNAL_LIBRARIES STREQUAL "AUTO"))
+if (NOT ENABLE_EXTERNAL_LIBRARIES)
     find_package(Boost REQUIRED)
     find_package(FFTW3F REQUIRED)
     if(NOT ANDROID)
-        find_package(LibUSB REQUIRED)  # used by so many packages
+        find_package(LibUSB REQUIRED)
     endif()
+elseif(ENABLE_EXTERNAL_LIBRARIES STREQUAL "AUTO")
+    find_package(Boost)
+    find_package(FFTW3F)
+    if(NOT ANDROID)
+        find_package(LibUSB)
+    endif()
+endif()
+
+if (NOT ENABLE_EXTERNAL_LIBRARIES OR (ENABLE_EXTERNAL_LIBRARIES STREQUAL "AUTO"))
     find_package(OpenCV OPTIONAL_COMPONENTS core highgui imgproc imgcodecs videoio) # channeltx/modatv
     find_package(LibSigMF) # SigMF recording files support
     find_package(ZLIB) # For DAB
@@ -770,20 +779,22 @@ if (NOT ENABLE_EXTERNAL_LIBRARIES OR (ENABLE_EXTERNAL_LIBRARIES STREQUAL "AUTO")
     if(ENABLE_RTLSDR)
         find_package(LibRTLSDR)
     endif()
-    if(ENABLE_SDRPLAY)
-        find_package(SDRplay)
-    endif()
     if(ENABLE_SOAPYSDR)
         find_package(SoapySDR)
     endif()
-    if(ENABLE_XTRX)
-        find_package(LibXTRX)
-    endif()
     if(ENABLE_USRP)
         find_package(UHD)
     endif()
 endif()
 
+# The following devices can't yet be built by external/CMakeLists.txt, so always call find_package
+if(ENABLE_SDRPLAY)
+    find_package(SDRplay)
+endif()
+if(ENABLE_XTRX)
+    find_package(LibXTRX)
+endif()
+
 if(ENABLE_EXTERNAL_LIBRARIES)
     add_subdirectory(external)
     find_package(Boost REQUIRED)
diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
index 72092ac64..99bcd7f4a 100644
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -269,7 +269,7 @@ endif (NOT OPUS_FOUND AND NOT USE_PRECOMPILED_LIBS)
 
 if (NOT ZLIB_FOUND AND NOT USE_PRECOMPILED_LIBS)
     ExternalProject_Add(zlib
-            URL https://zlib.net/zlib-1.2.13.tar.gz
+            URL https://zlib.net/current/zlib.tar.gz
             PREFIX "${EXTERNAL_BUILD_LIBRARIES}/zlib"
             CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix=<INSTALL_DIR>
             TEST_COMMAND ""
diff --git a/plugins/feature/gs232controller/inputcontroller.cpp b/plugins/feature/gs232controller/inputcontroller.cpp
index d9b8cf891..4e60d6014 100644
--- a/plugins/feature/gs232controller/inputcontroller.cpp
+++ b/plugins/feature/gs232controller/inputcontroller.cpp
@@ -15,6 +15,8 @@
 // along with this program. If not, see <http://www.gnu.org/licenses/>.          //
 ///////////////////////////////////////////////////////////////////////////////////
 
+#include <cmath>
+
 #ifdef QT_GAMEPAD_FOUND
 #include <QGamepadManager>
 #include "gamepadinputcontroller.h"
@@ -25,7 +27,7 @@
 double InputController::getAxisCalibratedValue(int axis, InputControllerSettings *settings, bool highSensitvity)
 {
     double value = getAxisValue(axis);
-    double absValue = abs(value);
+    double absValue = std::abs(value);
     double l = settings->m_deadzone[axis] / 100.0;
     if (absValue < l) {
         // Set to 0 if in deadzone