Another --disable-checking bootstrap failure

[Richard Kenner]

    Is anyone seeing this on a --disable-checking bootstrap?

    (gdb) bt
    #0  0x000000000090bba3 in lookup_page_table_entry (p=0xd3a170)
        at bld/gcc/src.x86-64/gcc/ggc-page.c:581
    #1  0x0000000000909b3c in ggc_set_mark (p=0xd3a170)
        at bld/gcc/src.x86-64/gcc/ggc-page.c:1254
    #2  0x00000000006d7751 in gt_ggc_mx_basic_block_def (x_p=0x2a962032a0)
        at gtype-desc.c:437
    #3  0x0000000000428e77 in gt_ggc_mx_lang_tree_node (x_p=0x2a96207c80)
        at gt-c-decl.h:228
    #4  0x00000000006d71fa in gt_ggc_mx_dataflow_d (x_p=0x2a9622da00)
        at gtype-desc.c:288
    #5  0x00000000006d7512 in gt_ggc_mx_tree_ann_d (x_p=0x2a96202690)
        at gtype-desc.c:365

This looks similar to the SIGSEGV I get compiling the Ada rts module
g-awk.adb with checking *enabled*.