No libm on Win32.

src/syncterm/CMakeLists.txt

@@ -87,8 +87,9 @@ target_include_directories(syncterm PRIVATE ../comio)
 target_include_directories(syncterm PRIVATE ../smblib)
 if(WIN32)
 	include_directories(syncterm PRIVATE ../../3rdp/win32.release/cryptlib/include)
+else()
+	target_link_libraries(syncterm m)
 endif()
-target_link_libraries(syncterm m)
 if(NOT HAS_CRYPTLIB_H)
     target_compile_definitions(syncterm PRIVATE WITHOUT_CRYPTLIB)
 endif()