Version 11.00 added multi-threading support, but we need to link to -lpthread
to resolve symbols.

--- CMakeLists.txt.orig	2025-09-05 10:46:54 UTC
+++ CMakeLists.txt
@@ -6,6 +6,8 @@ option(BUILD_UTIL "Build the mac command line tool" ON
 option(BUILD_SHARED "Build libMAC as a shared library" ON)
 option(BUILD_UTIL "Build the mac command line tool" ON)
 
+find_package(Threads)
+
 #
 # Determine interface version
 #
@@ -229,6 +231,7 @@ if(BUILD_SHARED)
 if(BUILD_SHARED)
     add_library(MAC SHARED $<TARGET_OBJECTS:shared> $<TARGET_OBJECTS:objects>)
     set_target_properties(MAC PROPERTIES VERSION ${MAC_SOVERSION} SOVERSION ${MAC_SOVERSION})
+    target_link_libraries(MAC Threads::Threads)
 
     if(WIN32)
         if(${ARCHITECTURE} STREQUAL x86)
@@ -315,7 +318,7 @@ if(BUILD_UTIL)
        Source/Console/Console.cpp)
 
     add_executable(macutil ${MAC_UTIL_HEADER_FILES} ${MAC_UTIL_SOURCE_FILES} $<TARGET_OBJECTS:shared>)
-    target_link_libraries(macutil MAC)
+    target_link_libraries(macutil MAC Threads::Threads)
 
     target_include_directories(macutil PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/Source/MACLib
