mtrace: Wean away from malloc hooks

Wean mtrace away from the malloc hooks and move them into the debug
DSO.  Split the API away from the implementation so that we can add
the API to libc.so as well as libc_malloc_debug.so, with the libc
implementations being empty.

Update localplt data since memalign no longer has any callers after
this change.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

sysdeps/unix/sysv/linux/m68k/coldfire/libc_malloc_debug.abilist

@@ -11,6 +11,8 @@ GLIBC_2.4 mcheck_check_all F
 GLIBC_2.4 mcheck_pedantic F
 GLIBC_2.4 memalign F
 GLIBC_2.4 mprobe F
+GLIBC_2.4 mtrace F
+GLIBC_2.4 muntrace F
 GLIBC_2.4 posix_memalign F
 GLIBC_2.4 pvalloc F
 GLIBC_2.4 realloc F

sysdeps/unix/sysv/linux/m68k/coldfire/localplt.data

@@ -2,7 +2,6 @@ libc.so: __m68k_read_tp
 libc.so: calloc
 libc.so: free
 libc.so: malloc
-libc.so: memalign
 libc.so: realloc
 libm.so: matherr
 # The TLS-enabled version of these functions is interposed from libc.so.

sysdeps/unix/sysv/linux/m68k/m680x0/libc_malloc_debug.abilist

@@ -8,6 +8,8 @@ GLIBC_2.0 malloc F
 GLIBC_2.0 mcheck F
 GLIBC_2.0 memalign F
 GLIBC_2.0 mprobe F
+GLIBC_2.0 mtrace F
+GLIBC_2.0 muntrace F
 GLIBC_2.0 pvalloc F
 GLIBC_2.0 realloc F
 GLIBC_2.0 valloc F

sysdeps/unix/sysv/linux/m68k/m680x0/localplt.data

@@ -3,7 +3,6 @@ libc.so: __m68k_read_tp
 libc.so: calloc
 libc.so: free
 libc.so: malloc
-libc.so: memalign
 libc.so: realloc
 libm.so: matherr
 # The TLS-enabled version of these functions is interposed from libc.so.