gcc failing on Darwin

[Jason Bacon <outpaddling%yahoo.com@localhost>]

gcc7, 8, and 9 are all failing for me on Darwin with errors like those 
shown below.  Anyone else seeing this?

    JB

../../../gcc-7.5.0/libgcc/unwind-dw2.c:1215:28: error: expected ';' 
before 'utm'
    offset = (_Unwind_Word) utmp * fs->data_align;
                            ^~~~
../../../gcc-7.5.0/libgcc/unwind-dw2.c: In function 'uw_frame_state_for':
../../../gcc-7.5.0/libgcc/unwind-dw2.c:1281:7: error: unknown type name 
'_uleb128_t'; did you mean '__uint128_t'?
       _uleb128_t i;
       ^~~~~~~~~~
       __uint128_t
../../../gcc-7.5.0/libgcc/unwind-dw2.c:1282:11: warning: assignment 
makes pointer from integer without a cast [-Wint-conversion]
       aug = read_uleb128 (aug, &i);
           ^
../../../gcc-7.5.0/libgcc/unwind-dw2.c:1287:7: error: unknown type name 
'_Unwind_Ptr'; did you mean '_Unwind_Action'?
       _Unwind_Ptr lsda;
       ^~~~~~~~~~~
       _Unwind_Action
../../../gcc-7.5.0/libgcc/unwind-dw2.c:1289:11: warning: assignment 
makes pointer from integer without a cast [-Wint-conversion]
       aug = read_encoded_value (context, fs->lsda_encoding, aug, &lsda);
           ^