code warnings in ezxml.c and nczarr_test/bm_chunks3.c

[edwardhartnett]

In current master, I see:

ezxml.c: In function ‘ezxml_parse_fd’:
ezxml.c:669:13: warning: implicit declaration of function ‘read’; did you mean ‘fread’? [-Wimplicit-function-declaration]
  669 |         l = read(fd, m = malloc(st.st_size), st.st_size);
      |             ^~~~
      |             fread
ezxml.c: In function ‘ezxml_parse_file’:
ezxml.c:685:18: warning: implicit declaration of function ‘close’; did you mean ‘pclose’? [-Wimplicit-function-declaration]
  685 |     if (fd >= 0) close(fd);
      |                  ^~~~~
      |                  pclose

Also, with --enable-benchmarks:

In file included from bm_utils.h:93,
                 from bm_chunks3.c:22:
bm_chunks3.c: In function ‘main’:
bm_chunks3.c:170:13: warning: implicit declaration of function ‘getoptions’; did you mean ‘bm_getoptions’? [-Wimplicit-function-declaration]
  170 |     NCCHECK(getoptions(&argc,&argv,&bmoptions));
      |             ^~~~~~~~~~
ut_test.h:66:32: note: in definition of macro ‘NCCHECK’
   66 | #define NCCHECK(expr) nccheck((expr),__LINE__)
      |                                ^~~~
bm_chunks3.c:171:13: warning: implicit declaration of function ‘nc4_buildpath’; did you mean ‘bm_buildpath’? [-Wimplicit-function-declaration]
  171 |     NCCHECK(nc4_buildpath(&bmoptions,&path));
      |             ^~~~~~~~~~~~~
ut_test.h:66:32: note: in definition of macro ‘NCCHECK’
   66 | #define NCCHECK(expr) nccheck((expr),__LINE__)
      |                                ^~~~
bm_chunks3.c:174:9: warning: implicit declaration of function ‘reportoptions’; did you mean ‘bm_reportoptions’? [-Wimplicit-function-declaration]
  174 |         reportoptions(&bmoptions);
      |         ^~~~~~~~~~~~~
      |         bm_reportoptions
bm_chunks3.c:175:9: warning: implicit declaration of function ‘reportmetaoptions’; did you mean ‘bm_reportmetaoptions’? [-Wimplicit-function-declaration]
  175 |         reportmetaoptions(&bmoptions.meta);
      |         ^~~~~~~~~~~~~~~~~
      |         bm_reportmetaoptions
bm_chunks3.c:325:5: warning: implicit declaration of function ‘clearoptions’; did you mean ‘bm_clearoptions’? [-Wimplicit-function-declaration]
  325 |     clearoptions(&bmoptions);
      |     ^~~~~~~~~~~~
      |     bm_clearoptions

[Dave-Allured]

Please add this issue to milestone 4.8.2. The Dec. 20 netcdf-c snapshot (main) failed in this way for me on Mac OS 10.15.7 Catalina and Apple clang version 12.0.0.