or1k: Fix compilation for __OR1K_MULTICORE__ builds

When building newlib for multicore environments we specify __OR1K_MULTICORE__
which switches the build to allocate one struct _or1k_reent per CPU
dynamiocally.

This was using a strange definition of (*_or1k_reent)[], and causing
the following compiler error:

    ./gnu-toolchain/newlib/libgloss/or1k/impure.c: In function ‘_or1k_reent_init’:
    ./gnu-toolchain/newlib/libgloss/or1k/impure.c:121:21: error: assignment to ‘struct ..
      121 |         _or1k_reent = (struct _or1k_reent*) _sbrk_r(0, memsize);
	  |

Fix this compiler error by changing the or1k_reent definition to a pointer
to structs.

Signed-off-by: Stafford Horne <[email protected]>

Author: stffrdhrn

libgloss/or1k/impure.c

@@ -108,7 +108,7 @@ _or1k_libc_getreent(void) {
 }
 
 #ifdef __OR1K_MULTICORE__
-struct _or1k_reent (*_or1k_reent)[];
+struct _or1k_reent *_or1k_reent;
 #else
 struct _or1k_reent _or1k_reent;
 #endif

libgloss/or1k/or1k-internals.h

@@ -55,8 +55,8 @@ struct _or1k_reent {
 
 
 #ifdef __OR1K_MULTICORE__
-extern struct _or1k_reent (*_or1k_reent)[];
-#define OR1K_REENT (*_or1k_reent)[or1k_coreid()]
+extern struct _or1k_reent *_or1k_reent;
+#define OR1K_REENT _or1k_reent[or1k_coreid()]
 #else
 extern struct _or1k_reent _or1k_reent;
 #define OR1K_REENT _or1k_reent