diff --git a/src/backend/port/dynloader/linux.h b/src/backend/port/dynloader/linux.h
index db2ac66..34fd35c 100644
--- a/src/backend/port/dynloader/linux.h
+++ b/src/backend/port/dynloader/linux.h
@@ -25,8 +25,12 @@
 /*
  * In some older systems, the RTLD_NOW flag isn't defined and the mode
  * argument to dlopen must always be 1.  The RTLD_GLOBAL flag is wanted
- * if available, but it doesn't exist everywhere.
- * If it doesn't exist, set it to 0 so it has no effect.
+ * if available, but it doesn't exist everywhere. The RTLD_DEEPBIND flag
+ * may also be missing, but if it is available we want to enable it so
+ * extensions we load prefer symbols from libraries they were linked
+ * against to conflicting symbols from unrelated libraries loaded by
+ * PostgreSQL.
+ * If the optional flags don't exist, set them to 0 so they have no effect.
  */
 #ifndef RTLD_NOW
 #define RTLD_NOW 1
@@ -34,8 +38,11 @@
 #ifndef RTLD_GLOBAL
 #define RTLD_GLOBAL 0
 #endif
+#ifndef RTLD_DEEPBIND
+#define RTLD_DEEPBIND 0
+#endif
 
-#define pg_dlopen(f)	dlopen((f), RTLD_NOW | RTLD_GLOBAL)
+#define pg_dlopen(f)	dlopen((f), RTLD_NOW | RTLD_GLOBAL | RTLD_DEEPBIND)
 #define pg_dlsym		dlsym
 #define pg_dlclose		dlclose
 #define pg_dlerror		dlerror