Remove ^L characters hidden randomly in the code. Not those used in text files as delimiters.

While working on a tool that processes Erlang code and testing it against this repo,
I found out about those little sneaky 0xff. I thought it may be of help to other
people build such tools to remove non-conforming-to-standard characters.
Add iodata, nonempty_string to built-in type highlighting for emacs

These built-in types were missing from emacs highlighting
Merge branch 'fenollp/treewide_remove_unexpected_0xff/OTP-11323' into maint

* fenollp/treewide_remove_unexpected_0xff/OTP-11323:
  Remove ^L characters hidden randomly in the code. Not those used in text files as delimiters.
tools: Add Erlang-specific compilation error regexp for erlang-eunit

This defvar was removed in a87a9699735b0a25f99397fba9576f5756da54d3 which made
eunit fail on running tests in emacs.
Merge branch 'puzza007/emacs_iodata_nonempty_string_builtin_types/OTP-11394' into maint

* puzza007/emacs_iodata_nonempty_string_builtin_types/OTP-11394:
  Add iodata, nonempty_string to built-in type highlighting for emacs
Take compiler options from beam in cover:compile_beam

Similarly to cover compiling from source
(in this case some user specified compiler options are allowed)
when cover compiling from existing beam
take a filtered list of compiler options from the beamfile.
This way e.g. export_all can be preserved. See use case in eb02beb1c3
tools: Fix compile_beam_opts testcase
Silence warnings about different buffer types in erl_memory

erl_memory.c:861:19: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    *p += sprintf(*p, "%*" USGND_INT_MAX_FSTR " ", fw, mi->size);
                  ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:863:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p,
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:869:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p, "%*" USGND_INT_MAX_FSTR " ", fw, mi->no);
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:871:20: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
            *p += sprintf(*p,
                          ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:878:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p,
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:900:19: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    *p += sprintf(*p, "%*" USGND_INT_MAX_FSTR " ", fw, mi->max_ever_size);
                  ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:902:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p, "%*s %*s ", fw, "", fw, "");
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:904:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p, "%*" USGND_INT_MAX_FSTR " ", fw, mi->max_ever_no);
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:906:20: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
            *p += sprintf(*p, "%*s %*s ", fw, "", fw, "");
                          ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:909:16: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        *p += sprintf(*p, "%*s %*s %*s ", fw, "", fw, "", fw, "");
                      ^~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:986:25: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    area.size = sprintf(area.ptr, format, carg);
                        ^~~~~~~~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1103:25: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    area.size = sprintf(area.ptr,
                        ^~~~~~~~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1109:23: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        area.size += sprintf(area.ptr + area.size,
                             ^~~~~~~~~~~~~~~~~~~~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1120:26: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    area.size += sprintf(area.ptr + area.size,
                         ^~~~~~~~~~~~~~~~~~~~
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1190:18: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    p += sprintf(p, "> %-*s", EM_TIME_FIELD_WIDTH - 2, "Maximum:");
                 ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1223:18: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    p += sprintf(p, "\n");
                 ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1227:15: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        p += sprintf(p, "%s", stop_str);
                     ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1230:15: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        p += sprintf(p, exit_str, state->info.exit_status);
                     ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1236:18: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    p += sprintf(p, format, tsz, bw);
                 ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1286:18: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    p += sprintf(p, "%*" USGND_INT_32_FSTR " ", EM_TIME_FIELD_WIDTH - 1, secs);
                 ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:1311:18: warning: passing 'usgnd_int_8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
    p += sprintf(p, "\n");
                 ^
/usr/include/secure/_stdio.h:49:28: note: expanded from macro 'sprintf'
  __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                           ^
erl_memory.c:2231:32: warning: passing 'char *' to parameter of type 'usgnd_int_8 *' (aka 'unsigned char *') converts between pointers to integer types with different sign [-Wpointer-sign]
    size = write_header(state, state->output.header, 1);
                               ^~~~~~~~~~~~~~~~~~~~
erl_memory.c:736:44: note: passing argument to parameter 'ptr' here
write_header(em_state *state, usgnd_int_8 *ptr, int trunc)
                                           ^
Silence warnings about socklen_t pointers sign in erl_memory

erl_memory.c:947:7: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different sign [-Wpointer-sign]
                    &saddr_size) != 0)
                    ^~~~~~~~~~~
/usr/include/sys/socket.h:616:74: note: passing argument to parameter here
int     getsockname(int, struct sockaddr * __restrict, socklen_t * __restrict)
                                                                             ^

erl_memory.c:2613:57: warning: passing 'int *' to parameter of type 'socklen_t *' (aka 'unsigned int *') converts between pointers to integer types with different sign [-Wpointer-sign]
    sock = accept(lsock, (struct sockaddr *) &oth_addr, &oth_addr_len);
                                                        ^~~~~~~~~~~~~
/usr/include/sys/socket.h:610:69: note: passing argument to parameter here
int     accept(int, struct sockaddr * __restrict, socklen_t * __restrict)
                                                                        ^
Prepare release