Use sourceforge for Boost as faster to download.

Use Boost 1.78.0 on Intel Mac, as 1.83 causes UHD to fail to load at runtime.
Fix Lame link on Mac arm64

external/CMakeLists.txt

@@ -31,6 +31,15 @@ set(SOAPYSDR_REMOTE_TAG "soapy-remote-0.5.1")
 set(AIRSPY_TAG "37c768ce9997b32e7328eb48972a7fda0a1f8554")
 set(HACKRF_TAG "v2022.09.1")
 set(LIBXML2_TAG "v2.10.4")
+set(UHD_TAG "v4.5.0.0")
+if (APPLE AND (CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL x86_64))
+    # UHD fails to load with 1.80+
+    set(BOOST_TAG "1.78.0")
+    set(BOOST_TAG2 "1_78_0")
+else()
+    set(BOOST_TAG "1.83.0")
+    set(BOOST_TAG2 "1_83_0")
+endif()
 
 # For some external project macros
 include(ExternalProject)
@@ -340,7 +349,7 @@ endif (NOT FFTW3F_FOUND AND NOT USE_PRECOMPILED_LIBS)
 # So instead, we use FetchContent and build Boost at CMake configure time
 include(FetchContent)
 FetchContent_Declare(boost
-    URL https://boostorg.jfrog.io/artifactory/main/release/1.83.0/source/boost_1_83_0.tar.gz
+    URL "https://sourceforge.net/projects/boost/files/boost/${BOOST_TAG}/boost_${BOOST_TAG2}.tar.gz/download"
 )
 
 find_package(Boost QUIET)
@@ -483,7 +492,11 @@ if (NOT FFMPEG_FOUND AND NOT USE_PRECOMPILED_LIBS)
         # ffmpeg doesn't try to use pkg-config for lame, as it doesn't include a .pc file
         #set(LAME_PKG_CONFIG_DIR "${install_dir}/lib/pkgconfig")
         set(LAME_EXTRA_CFLAGS "-I${install_dir}/include")
-        set(LAME_EXTRA_LDFLAGS "-L${install_dir}/lib")
+        if (APPLE AND (CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL arm64))
+            set(LAME_EXTRA_LDFLAGS "-L${install_dir}/lib -Wl,-ld_classic")
+        else()
+            set(LAME_EXTRA_LDFLAGS "-L${install_dir}/lib")
+        endif()
         set_global_cache(LAME_FOUND ON)
         set(LAME_EXTERNAL ON CACHE INTERNAL "")
         if (APPLE)
@@ -1491,7 +1504,7 @@ if (WIN32 OR APPLE)
         endif ()
         ExternalProject_Add(uhd
                 GIT_REPOSITORY https://github.com/EttusResearch/uhd.git
-                GIT_TAG v4.5.0.0
+                GIT_TAG ${UHD_TAG}
                 DEPENDS ${LIBUSB_DEPENDS} ${Boost_DEPENDS}
                 PREFIX "${EXTERNAL_BUILD_LIBRARIES}/uhd"
                 SOURCE_SUBDIR "host"