meson: fix build for FreeBSD/clang compatibility

Remove GCC-specific static link args (-static, -static-libgcc,
-static-libstdc++) that fail under clang. Add threads_dep via
dependency('threads') to all targets so Boost ASIO's pthread
usage links correctly on FreeBSD where clang does not pull it in
implicitly. Linux/GCC builds are unaffected.

meson.build

@@ -6,30 +6,32 @@ project('finger', 'cpp',
 # Find Boost dependencies - prefer static libraries
 boost_dep = dependency('boost', modules : ['system'], static : true)
 
+# pthreads — required by Boost ASIO; clang on FreeBSD does not link it implicitly
+threads_dep = dependency('threads')
+
 # Find Google Test and Google Mock dependencies
 gtest_dep = dependency('gtest', main : true, required : true)
 gmock_dep = dependency('gmock', main : true, required : true)
 
 executable('finger',
   'main.cpp','handler.cpp',
-  dependencies : [boost_dep],
-  link_args : ['-static', '-static-libgcc', '-static-libstdc++'],
+  dependencies : [boost_dep, threads_dep],
   install : true)
 
 # Test executable
 test_exe = executable('test_handler',
   'test_handler.cpp', 'handler.cpp',
-  dependencies : [boost_dep, gtest_dep, gmock_dep])
+  dependencies : [boost_dep, threads_dep, gtest_dep, gmock_dep])
 
 # Mock test executable
 test_mock_exe = executable('test_handler_mock',
   'test_handler_mock.cpp', 'handler.cpp',
-  dependencies : [boost_dep, gtest_dep, gmock_dep])
+  dependencies : [boost_dep, threads_dep, gtest_dep, gmock_dep])
 
 # Real filesystem test executable
 test_real_fs_exe = executable('test_handler_real_filesystem',
   'test_handler_real_filesystem.cpp', 'handler.cpp',
-  dependencies : [boost_dep, gtest_dep, gmock_dep])
+  dependencies : [boost_dep, threads_dep, gtest_dep, gmock_dep])
 
 # Register the tests
 test('handler_tests', test_exe)