Improve worker thread support by preventing unload on dlclose

docs/install.md

@@ -213,19 +213,6 @@ use the `FONTCONFIG_PATH` environment variable to point to a custom location.
 
 Embedded SVG fonts are unsupported.
 
-## Worker threads
-
-On some platforms, including glibc-based Linux,
-the main thread must call `require('sharp')`
-_before_ worker threads are created.
-This is to ensure shared libraries remain loaded in memory
-until after all threads are complete.
-
-Without this, the following error may occur:
-```
-Module did not self-register
-```
-
 ## Known conflicts
 
 ### Canvas and Windows

src/binding.gyp

@@ -170,9 +170,9 @@
                 '-l:libvips-cpp.so.42'
               ],
               'ldflags': [
-                # Ensure runtime linking is relative to sharp.node
                 '-Wl,-s',
                 '-Wl,--disable-new-dtags',
+                '-Wl,-z,nodelete',
                 '-Wl,-rpath=\'$$ORIGIN/../../sharp-libvips-<(platform_and_arch)/lib\'',
                 '-Wl,-rpath=\'$$ORIGIN/../../../<(sharp_libvips_version)/sharp-libvips-<(platform_and_arch)/lib\'',
                 '-Wl,-rpath=\'$$ORIGIN/../../node_modules/@img/sharp-libvips-<(platform_and_arch)/lib\'',