libhugeltbfs' linker uses system's linker instead of AT's

[mscastanho]

libhugetlbfs provides an ld wrapper to provide the hugepage-backed text/data/bss sections feature. This wrapper looks for the underlying ld to use by calling which -a ld if the LD environment variable is not set. When using the libhugetlbfs provided by AT, this ends up using the system's ld (see the line setting LD below) instead of AT's:

$ bash -x /opt/at15.0-0-beta2/share/libhugetlbfs/ld --help 
+ '[' -n '' ']'                                                                 
+ export LD_HUGETLBFS_RECURSION=1                                        
+ LD_HUGETLBFS_RECURSION=1                                                     
+ HUGETLB_LDSCRIPT_PATH=/opt/at15.0-0-beta2/share/libhugetlbfs/ldscripts
+ '[' -z /opt/at15.0-0-beta2/share/libhugetlbfs/ldscripts ']'                 
+ CUSTOM_LDSCRIPTS=no                                                        
+ '[' -z no ']'                                                      
+ '[' -z '' ']'                                                          
++ which -a ld                                                                          
+ for x in $(which -a ld)                                                   
+ '[' /usr/bin/ld '!=' /opt/at15.0-0-beta2/share/libhugetlbfs/ld ']'              
+ LD=/usr/bin/ld                                                                   
+ break                                                                              
+ i=0                                                                                 
+ '[' -n --help ']'                                                     
+ arg=--help                                                             
+ case "$arg" in                                                                                                                                                                                                                      
+ args[$i]=--help                                                             
+ i=1                                                                                                                         
+ shift                                                            
+ '[' -n '' ']'                                                                    
+ '[' -n '' ']'                                                             
+ '[' -z '' ']'                                                                
+ '[' -n '' ']'                                                                     
++ tr -d ' '                                                                               
++ sed -n '/Supported emulations/{n;p}'                                       
++ ld -V                                                                
+ EMU=elf64lppc                                                           
+ '[' -z elf64lppc ']'                                                               
+ MB=1048576                                                            
+ case "$EMU" in                                                       
++ cat /proc/meminfo                                                      
++ grep Hugepagesize:                                                        
++ awk '{print $2}'                                                            
+ hpage_kb=                                                            
++ cat /proc/cpuinfo                                                        
++ grep MMU                                                          
++ awk '{ print $3}'                                                  
+ MMU_TYPE=Hash                                                                
+ HPAGE_SIZE=0                                                                   
+ '[' Hash == Hash ']'                                                         
+ SLICE_SIZE=268435456                                                  
+ '[' '' == slice ']'                                                   
+ /usr/bin/ld --help                                                      
Usage: /usr/bin/ld [options] file...

I hit this error while using AT's gcc with -B ${AT_DIR}/share/libhugetlbfs -Wl,--hugetlbfs-align. It ended up trying to load linker plugins from AT (containing glibc 2.33 symbols) using the system's linker, causing a crash.