[META] Build-time warnings

[p5pRT]

Migrated from rt.perl.org#133556 (status was 'new')

Searchable as RT133556$

[p5pRT]

From @jkeenan

This META ticket will serve as a place to reference other RTs whose
focus is on elimination of build-time ("C-level") warnings, i.e.,
warnings generated by 'make' or 'make test_prep'.

Tickets discussing problems with the warnings which perl itself
generates should not be referenced by this ticket, nor should Perl-level
warnings generated by modules which are shipped with the core distribution.

[p5pRT]

From @jkeenan

Summary of my perl5 (revision 5 version 25 subversion 11) configuration​:
  Derived from​: 295d6d0
  Platform​:
  osname=linux
  osvers=4.4.0-67-generic
  archname=x86_64-linux
  uname='linux zareason 4.4.0-67-generic #88-ubuntu smp wed mar 8 16​:34​:45 utc 2017 x86_64 x86_64 x86_64 gnulinux '
  config_args='-des -Dusedevel'
  hint=recommended
  useposix=true
  d_sigaction=define
  useithreads=undef
  usemultiplicity=undef
  use64bitint=define
  use64bitall=define
  uselongdouble=undef
  usemymalloc=n
  default_inc_excludes_dot=define
  bincompat5005=undef
  Compiler​:
  cc='cc'
  ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
  optimize='-O2'
  cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
  ccversion=''
  gccversion='5.4.0 20160609'
  gccosandvers=''
  intsize=4
  longsize=8
  ptrsize=8
  doublesize=8
  byteorder=12345678
  doublekind=3
  d_longlong=define
  longlongsize=8
  d_longdbl=define
  longdblsize=16
  longdblkind=3
  ivtype='long'
  ivsize=8
  nvtype='double'
  nvsize=8
  Off_t='off_t'
  lseeksize=8
  alignbytes=8
  prototype=define
  Linker and Libraries​:
  ld='cc'
  ldflags =' -fstack-protector-strong -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /lib64 /usr/lib64
  libs=-lpthread -lnsl -ldb -ldl -lm -lcrypt -lutil -lc
  perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
  libc=libc-2.23.so
  so=so
  useshrplib=false
  libperl=libperl.a
  gnulibc_version='2.23'
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs
  dlext=so
  d_dlsymun=undef
  ccdlflags='-Wl,-E'
  cccdlflags='-fPIC'
  lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong'

Characteristics of this binary (from libperl)​:
  Compile-time options​:
  HAS_TIMES
  PERLIO_LAYERS
  PERL_COPY_ON_WRITE
  PERL_DONT_CREATE_GVSV
  PERL_MALLOC_WRAP
  PERL_OP_PARENT
  PERL_PRESERVE_IVUV
  PERL_USE_DEVEL
  USE_64_BIT_ALL
  USE_64_BIT_INT
  USE_LARGE_FILES
  USE_LOCALE
  USE_LOCALE_COLLATE
  USE_LOCALE_CTYPE
  USE_LOCALE_NUMERIC
  USE_LOCALE_TIME
  USE_PERLIO
  USE_PERL_ATOF
  Locally applied patches​:
  uncommitted-changes
  Built under linux
  Compiled at Mar 21 2017 11​:18​:34
  %ENV​:
  PERLBREW_BASHRC_VERSION="0.78"
  PERLBREW_HOME="/home/jkeenan/.perlbrew"
  PERLBREW_MANPATH="/home/jkeenan/perl5/perlbrew/perls/perl-5.24.1/man"
  PERLBREW_PATH="/home/jkeenan/perl5/perlbrew/bin​:/home/jkeenan/perl5/perlbrew/perls/perl-5.24.1/bin"
  PERLBREW_PERL="perl-5.24.1"
  PERLBREW_ROOT="/home/jkeenan/perl5/perlbrew"
  PERLBREW_VERSION="0.78"
  PERL_WORKDIR="/home/jkeenan/gitwork/perl"
  @​INC​:
  lib
  /usr/local/lib/perl5/site_perl/5.25.11/x86_64-linux
  /usr/local/lib/perl5/site_perl/5.25.11
  /usr/local/lib/perl5/5.25.11/x86_64-linux
  /usr/local/lib/perl5/5.25.11