Fails to link if libpng/jpeg development libraries are missing.

[Quipyowert2]

Fails to link if libpng/jpeg development libraries are missing.

When compiling Tk 804.036, the following warning appears when configuring:
'pkg-config libpng' failed, continue with fallback values for cflags and libs...

This is because I have libpng16-devel installed which has libpng16.pc instead of plain libpng.pc. Because libpng was not found, the build system attempts to compile the bundled libpng. My brewed perl was compiled with _FORTIFY_SOURCE and -O2 and the build system picks up the _FORTIFY_SOURCE option, but ignores the optimization flag when compiling libpng/jpeg. This leads to the following warning when checking for <errno.h> in PNG/zlib/configure:405:

cc -c -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/inclu
de -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2 -o example test.c
In file included from /usr/include/errno.h:25,
                 from test.c:1:
/usr/include/features.h:414:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]
  414 | #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
      |    ^~~~~~~

As configure checks the compiler output against the empty string, it assumes that <errno.h> is not found, defining the NO_ERRNO_H macro. This leads to the errno global variable being declared in PNG/zlib/zutil.h:35. This non-thread local storage variable declaration clashes with the TLS definition in the version of glibc I have installed (which is 2.39), leading to the following error when linking:

> cc -fPIC -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2 -fPIC -DNO_snprintf -DHAS_sprintf_void -DNO_ERRNO_H -o example example.o -L. libz.a
/usr/lib64/gcc/x86_64-suse-linux/13/../../../../x86_64-suse-linux/bin/ld: errno: TLS definition in /lib64/libc.so.6 section .tbss mismatches non-TLS reference in libz.a(gzio.o)
/usr/lib64/gcc/x86_64-suse-linux/13/../../../../x86_64-suse-linux/bin/ld: /lib64/libc.so.6: error adding symbols: bad value

The fix is simple: Enable optimization by adding $Config{optimize} flag, which was -O2 on the Perl I brewed, to the CFLAGS for the bundled libpng and jpeg so that _FORTIFY_SOURCE, which was added to Perl's build system starting in 5.22, doesn't cause a warning.

diff --git a/JPEG/Makefile.jpeg.maybe b/JPEG/Makefile.jpeg.maybe
index 7bb9688b..063e53d3 100755
--- a/JPEG/Makefile.jpeg.maybe
+++ b/JPEG/Makefile.jpeg.maybe
@@ -32,7 +32,7 @@ if ($^O eq 'MSWin32')
 else
  {
   $ENV{CC} = $Config{cc};
-  local $ENV{CFLAGS} = "$Config{ccflags} $Config{cccdlflags}";
+  local $ENV{CFLAGS} = "$Config{ccflags} $Config{optimize} $Config{cccdlflags}";
   local $ENV{LDFLAGS} = "$Config{ccflags} $Config{ldflags}";
   system(sh => "./configure");
  }
diff --git a/PNG/Makefile.zlib.maybe b/PNG/Makefile.zlib.maybe
index 6da4ba9a..abe519b8 100644
--- a/PNG/Makefile.zlib.maybe
+++ b/PNG/Makefile.zlib.maybe
@@ -26,7 +26,7 @@ if ($^O eq 'MSWin32')
 else
  {
   $ENV{CC} = $Config{cc};
-  local $ENV{CFLAGS} = "$Config{ccflags} $Config{cccdlflags}";
+  local $ENV{CFLAGS} = "$Config{ccflags} $Config{optimize} $Config{cccdlflags}";
   system(sh => "./configure");
  }

VERSIONS

Perl 5.41.2 (installed from source with Perlbrew)
CPAN: 1.64
GCC 13.3.0 (official Tumbleweed package)
GLIBC 2.39 (official Tumbleweed package)
openSUSE Tumbleweed 20240725-0 (Last month's snapshot)
perl-Tk version: 804.036-18-gf0bb386b
libPNG: libpng16-16 libpng16-devel
libJPEG: libjpeg8 (don't have -devel package installed at the moment)
ld.bfd version: GNU ld (GNU Binutils; openSUSE Tumbleweed) 2.42.0.20240130-4
WSL2 version:

WSL version: 2.2.4.0
Kernel version: 5.15.153.1-2
WSLg version: 1.0.61
MSRDC version: 1.2.5326
Direct3D version: 1.611.1-81528511
DXCore version: 10.0.26091.1-240325-1447.ge-release
Windows version: 10.0.19045.4780

perl -V

Summary of my perl5 (revision 5 version 41 subversion 2) configuration:

  Platform:
    osname=linux
    osvers=5.15.153.1-microsoft-standard-wsl2
    archname=x86_64-linux
    uname='linux msi 5.15.153.1-microsoft-standard-wsl2 #1 smp fri mar 29 23:14:13 utc 2024 x86_64 x86_64 x86_64 gnulinux '
    config_args='-de -Dprefix=/home/nathan/perl5/perlbrew/perls/perl-5.41.2 -Dusedevel -Aeval:scriptdir=/home/nathan/perl5/perlbrew/perls/perl-5.41.2/bin'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
  Compiler:
    cc='cc'
    ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
    optimize='-O2'
    cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='13.3.0'
    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/x86_64-suse-linux/lib /usr/lib /usr/lib64 /usr/local/lib64
    libs=-lpthread -ldl -lm -lcrypt -lutil -lc
    perllibs=-lpthread -ldl -lm -lcrypt -lutil -lc
    libc=/lib/../lib64/libc.so.6
    so=so
    useshrplib=false
    libperl=libperl.a
    gnulibc_version='2.39'
  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_LONG_DOUBLE
    HAS_STRTOLD
    HAS_TIMES
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_HASH_FUNC_SIPHASH13
    PERL_HASH_USE_SBOX32
    PERL_MALLOC_WRAP
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    PERL_USE_DEVEL
    PERL_USE_SAFE_PUTENV
    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
  Built under linux
  Compiled at Aug 20 2024 15:21:53
  %ENV:
    PERLBREW_HOME="/home/nathan/.perlbrew"
    PERLBREW_MANPATH="/home/nathan/perl5/perlbrew/perls/perl-5.41.2/man"
    PERLBREW_PATH="/home/nathan/perl5/perlbrew/bin:/home/nathan/perl5/perlbrew/perls/perl-5.41.2/bin"
    PERLBREW_PERL="perl-5.41.2"
    PERLBREW_ROOT="/home/nathan/perl5/perlbrew"
    PERLBREW_SHELLRC_VERSION="0.98"
    PERLBREW_VERSION="0.98"
  @INC:
    /home/nathan/perl5/perlbrew/perls/perl-5.41.2/lib/site_perl/5.41.2/x86_64-linux
    /home/nathan/perl5/perlbrew/perls/perl-5.41.2/lib/site_perl/5.41.2
    /home/nathan/perl5/perlbrew/perls/perl-5.41.2/lib/5.41.2/x86_64-linux
    /home/nathan/perl5/perlbrew/perls/perl-5.41.2/lib/5.41.2