Index: libexec/rtld-elf/paths.h
===================================================================
--- libexec/rtld-elf/paths.h
+++ libexec/rtld-elf/paths.h
@@ -31,12 +31,20 @@
 
 #undef _PATH_ELF_HINTS
 
+#if defined(__ILP32__)
+#define	LD_			"LD_32_"
+#elif defined(__LP64__)
+#define	LD_			"LD_64_"
+#else
+#error "Unsupported pointer size"
+#endif
+#define	LD_FALLBACK_		"LD_"
+
 #ifdef COMPAT_32BIT
 #define	_PATH_ELF_HINTS		"/var/run/ld-elf32.so.hints"
 #define	_PATH_LIBMAP_CONF	"/etc/libmap32.conf"
 #define	_BASENAME_RTLD		"ld-elf32.so.1"
 #define	STANDARD_LIBRARY_PATH	"/lib32:/usr/lib32"
-#define	LD_			"LD_32_"
 #endif
 
 #ifndef _PATH_ELF_HINTS
@@ -59,10 +67,6 @@
 #define	STANDARD_LIBRARY_PATH	"/lib/casper:/lib:/usr/lib"
 #endif
 
-#ifndef LD_
-#define	LD_			"LD_"
-#endif
-
 #define	_PATH_SOFT_ELF_HINTS	"/var/run/ld-elf-soft.so.hints"
 #define	_PATH_SOFT_LIBMAP_CONF	"/etc/libmap-soft.conf"
 #define	_PATH_SOFT_RTLD		"/libexec/ld-elf.so.1"
Index: libexec/rtld-elf/rtld.1
===================================================================
--- libexec/rtld-elf/rtld.1
+++ libexec/rtld-elf/rtld.1
@@ -127,10 +127,22 @@
 recognizes a number of environment variables that can be used to modify
 its behaviour.
 On 64-bit architectures, the linker for 32-bit objects recognizes
-all the environment variables listed below, but is being prefixed with
-.Ev LD_32_ ,
+all the environment variables listed below but prefixed with
+.Ev LD_32_
+instead of
+.Ev LD_ ,
 for example:
 .Ev LD_32_TRACE_LOADED_OBJECTS .
+On 64-bit systems,
+.Nm
+also recognizes variables prefixed with
+.Ev LD_64_ .
+The variables prefixed with
+.Ev LD_32_
+or
+.Ev LD_64_
+have priority over the ones using
+.Ev LD_ .
 .Bl -tag -width ".Ev LD_LIBMAP_DISABLE"
 .It Ev LD_DUMP_REL_POST
 If set,
Index: libexec/rtld-elf/rtld.c
===================================================================
--- libexec/rtld-elf/rtld.c
+++ libexec/rtld-elf/rtld.c
@@ -353,6 +353,20 @@
 #define _LD(x)	LD_ x
 #endif
 
+/* Check LD_{32,64}_<VAR> and if that is not set fall back to LD_<VAR>. */
+#define get_ld_env(var) _get_ld_env(_LD(var), LD_FALLBACK_ var)
+
+static char *
+_get_ld_env(const char *preferred, const char *fallback)
+{
+	char *result;
+
+	result = getenv(preferred);
+	if (result == NULL && fallback != NULL)
+		result = getenv(fallback);
+	return (result);
+}
+
 /*
  * Main entry point for dynamic linking.  The first argument is the
  * stack pointer.  The stack is expected to be laid out as described
@@ -562,7 +576,7 @@
 	}
     }
 
-    ld_bind_now = getenv(_LD("BIND_NOW"));
+    ld_bind_now = get_ld_env("BIND_NOW");
 
     /* 
      * If the process is tainted, then we un-set the dangerous environment
@@ -580,17 +594,17 @@
 		rtld_die();
 	}
     }
-    ld_debug = getenv(_LD("DEBUG"));
+    ld_debug = get_ld_env("DEBUG");
     if (ld_bind_now == NULL)
-	    ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
-    libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
-    libmap_override = getenv(_LD("LIBMAP"));
-    ld_library_path = getenv(_LD("LIBRARY_PATH"));
-    ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
-    ld_preload = getenv(_LD("PRELOAD"));
-    ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
-    ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
-    library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
+	    ld_bind_not = get_ld_env("BIND_NOT") != NULL;
+    libmap_disable = get_ld_env("LIBMAP_DISABLE") != NULL;
+    libmap_override = get_ld_env("LIBMAP");
+    ld_library_path = get_ld_env("LIBRARY_PATH");
+    ld_library_dirs = get_ld_env("LIBRARY_PATH_FDS");
+    ld_preload = get_ld_env("PRELOAD");
+    ld_elf_hints_path = get_ld_env("ELF_HINTS_PATH");
+    ld_loadfltr = get_ld_env("LOADFLTR") != NULL;
+    library_path_rpath = get_ld_env("LIBRARY_PATH_RPATH");
     if (library_path_rpath != NULL) {
 	    if (library_path_rpath[0] == 'y' ||
 		library_path_rpath[0] == 'Y' ||
@@ -602,8 +616,8 @@
     dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
 	(ld_library_path != NULL) || (ld_preload != NULL) ||
 	(ld_elf_hints_path != NULL) || ld_loadfltr;
-    ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
-    ld_utrace = getenv(_LD("UTRACE"));
+    ld_tracing = get_ld_env("TRACE_LOADED_OBJECTS");
+    ld_utrace = get_ld_env("UTRACE");
 
     if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
 	ld_elf_hints_path = ld_elf_hints_default;
@@ -735,7 +749,7 @@
 	exit(0);
     }
 
-    if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
+    if (get_ld_env("DUMP_REL_PRE") != NULL) {
        dump_relocations(obj_main);
        exit (0);
     }
@@ -763,7 +777,7 @@
     if (do_copy_relocations(obj_main) == -1)
 	rtld_die();
 
-    if (getenv(_LD("DUMP_REL_POST")) != NULL) {
+    if (get_ld_env("DUMP_REL_POST") != NULL) {
        dump_relocations(obj_main);
        exit (0);
     }
@@ -4665,16 +4679,16 @@
     const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
     int c;
 
-    if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
+    if ((main_local = get_ld_env("TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
 	main_local = "";
 
-    if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
+    if ((fmt1 = get_ld_env("TRACE_LOADED_OBJECTS_FMT1")) == NULL)
 	fmt1 = "\t%o => %p (%x)\n";
 
-    if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
+    if ((fmt2 = get_ld_env("TRACE_LOADED_OBJECTS_FMT2")) == NULL)
 	fmt2 = "\t%o (%x)\n";
 
-    list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
+    list_containers = get_ld_env("TRACE_LOADED_OBJECTS_ALL");
 
     for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
 	Needed_Entry *needed;