Use LD_* variables for 32bits too instead of the FreeBSD invention LD_32_*.
We use LD_* everywhere on Gentoo and things like libtool wrappers have no clue
about LD_32_* and thus fail to run from the build directory.

diff -uNr libexec.old/rtld-elf/rtld.h libexec/rtld-elf/rtld.h
--- libexec.old/rtld-elf/rtld.h	2013-08-24 12:30:26.000000000 -0400
+++ libexec/rtld-elf/rtld.h	2013-08-26 17:10:19.000000000 -0400
@@ -47,7 +47,6 @@
 #define	_PATH_ELF_HINTS		"/var/run/ld-elf32.so.hints"
 /* For running 32 bit binaries  */
 #define	STANDARD_LIBRARY_PATH	"/lib32:/usr/lib32"
-#define LD_ "LD_32_"
 #endif
 
 #ifndef STANDARD_LIBRARY_PATH