Source: @Johnnynator
Upsteam: No
Subject: Musl always returns /lib/libQt5Core.so.5 for Dl_info.dli_fname. 
On GLIBC this seems to only happen with programs that load qt5-webengine(?)

---
diff --git qtbasesrc/corelib/global/qlibraryinfo.cpp qtbasesrc/corelib/global/qlibraryinfo.cpp
index 8bcf67e73d..28d7355310 100644
--- qtbase/src/corelib/global/qlibraryinfo.cpp
+++ qtbase/src/corelib/global/qlibraryinfo.cpp
@@ -558,6 +558,12 @@ static QString getRelocatablePrefix()
     int result = dladdr(reinterpret_cast<void *>(&QLibraryInfo::isDebugBuild), &info);
     if (result > 0 && info.dli_fname)
         prefixPath = prefixFromQtCoreLibraryHelper(QString::fromLatin1(info.dli_fname));
+#if 1
+    QDir preDir(prefixPath);
+    if (preDir.isRoot()) {
+        prefixPath = QStringLiteral("/usr");
+    }
+#endif
 #elif defined(Q_OS_WIN)
     HMODULE hModule = getWindowsModuleHandle();
     const int kBufferSize = 4096;