ARC: Conditionalise certain relocations as provided by TLS tools only

uClibc mainline supports NPTL which in turns depends on TLS support in
the tools (gcc/binutils), which is yet to be merged in dev branches.

However there is some non NPTL code in uClibc, added as part of NPTL
effort, which relies on certain relocations only provided by NPTL
binutils. As a result building the current upstream even for LT.old
breaks.

So conditionalize that code on tools, bu tin lack of specific versions,
we use NPTL enabling as a sign the tools are equipped to handle those
relos.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

extra/Configs/defconfigs/arc/defconfig

@@ -6,7 +6,7 @@ KERNEL_HEADERS="%KERNEL_HEADERS%"
 # LDSO_CACHE_SUPPORT is not set
 LDSO_RUNPATH=y
 # LDSO_SAFE_RUNPATH is not set
-UCLIBC_HAS_THREADS_NATIVE=y
+LINUXTHREADS_OLD=y
 PTHREADS_DEBUG_SUPPORT=y
 UCLIBC_HAS_OBSTACK=y
 UCLIBC_SUSV2_LEGACY=y

ldso/ldso/arc/dl-startup.h

@@ -33,9 +33,16 @@ __asm__(
     "   ; If ldso ran as cmd with executable file nm as arg     \n"
     "   ; skip the extra args calc by dl_start()                \n"
     "   ld_s    r1, [sp]       ; orig argc from aux-vec Tbl     \n"
+
+#ifdef __UCLIBC_HAS_THREADS_NATIVE__
     "   ld      r12, [pcl, _dl_skip_args@pcl]                   \n"
 
     "   add     r2, pcl, _dl_fini@pcl       ; finalizer         \n"
+#else
+    "   add     r12, pcl, _dl_skip_args-.+(.&2)                 \n"
+    "   ld      r12, [r12]                                      \n"
+    "   add     r2, pcl, _dl_fini-.+(.&2)   ; finalizer         \n"
+#endif
 
     "   add2    sp, sp, r12    ; discard argv entries from stack\n"
     "   sub_s   r1, r1, r12    ; adjusted argc, on stack        \n"

ldso/ldso/arc/dl-sysdep.h

@@ -127,6 +127,7 @@ static __always_inline Elf32_Addr elf_machine_dynamic(void)
 /* Return the run-time load address of the shared object.  */
 static __always_inline Elf32_Addr elf_machine_load_address(void)
 {
+#ifdef __UCLIBC_HAS_THREADS_NATIVE__
     /* To find the loadaddr we subtract the runtime addr of a non-local symbol
      * say _DYNAMIC from it's build-time addr.
      * N.B., gotpc loads get optimized by the linker if it finds the symbol
@@ -144,6 +145,15 @@ static __always_inline Elf32_Addr elf_machine_load_address(void)
         "sub %0, %0, %1                ;delta"                    "\n"
         : "=&r" (addr), "=r"(tmp)
     );
+#else
+	Elf32_Addr addr, tmp;
+	__asm__ (
+        "ld  %1, [pcl, _dl_start@gotpc] ;build addr of _dl_start   \n"
+        "add %0, pcl, _dl_start-.+(.&2) ;runtime addr of _dl_start \n"
+        "sub %0, %0, %1                 ;delta                     \n"
+         : "=&r" (addr), "=r"(tmp)
+     );
+#endif
 	return addr;
 }