1 package ExtUtils::Liblist;
3 # Broken out of MakeMaker from version 4.11
5 $VERSION = substr q$Revision: 1.25 $, 10;
12 if ($^O eq 'VMS') { return &_vms_ext; }
13 elsif($^O eq 'MSWin32') { return &_win32_ext; }
14 else { return &_unix_os2_ext; }
18 my($self,$potential_libs, $verbose) = @_;
19 if ($^O =~ 'os2' and $Config{libs}) {
20 # Dynamic libraries are not transitive, so we may need including
21 # the libraries linked against perl.dll again.
23 $potential_libs .= " " if $potential_libs;
24 $potential_libs .= $Config{libs};
26 return ("", "", "", "") unless $potential_libs;
27 warn "Potential libraries are '$potential_libs':\n" if $verbose;
29 my($so) = $Config{'so'};
30 my($libs) = $Config{'libs'};
31 my $Config_libext = $Config{lib_ext} || ".a";
34 # compute $extralibs, $bsloadlibs and $ldloadlibs from
36 # this is a rewrite of Andy Dougherty's extliblist in perl
38 my(@searchpath); # from "-L/path" entries in $potential_libs
39 my(@libpath) = split " ", $Config{'libpth'};
40 my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen);
41 my($fullname, $thislib, $thispth, @fullname);
42 my($pwd) = cwd(); # from Cwd.pm
45 foreach $thislib (split ' ', $potential_libs){
47 # Handle possible linker path arguments.
48 if ($thislib =~ s/^(-[LR])//){ # save path flag type
51 warn "$ptype$thislib ignored, directory does not exist\n"
55 unless ($self->file_name_is_absolute($thislib)) {
56 warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n";
57 $thislib = $self->catdir($pwd,$thislib);
59 push(@searchpath, $thislib);
60 push(@extralibs, "$ptype$thislib");
61 push(@ldloadlibs, "$ptype$thislib");
65 # Handle possible library arguments.
66 unless ($thislib =~ s/^-l//){
67 warn "Unrecognized argument in LIBS ignored: '$thislib'\n";
72 foreach $thispth (@searchpath, @libpath){
74 # Try to find the full name of the library. We need this to
75 # determine whether it's a dynamically-loadable library or not.
76 # This tends to be subject to various os-specific quirks.
77 # For gcc-2.6.2 on linux (March 1995), DLD can not load
78 # .sa libraries, with the exception of libm.sa, so we
79 # deliberately skip them.
81 $self->lsdir($thispth,"^\Qlib$thislib.$so.\E[0-9]+")){
82 # Take care that libfoo.so.10 wins against libfoo.so.9.
83 # Compare two libraries to find the most recent version
84 # number. E.g. if you have libfoo.so.9.0.7 and
85 # libfoo.so.10.1, first convert all digits into two
86 # decimal places. Then we'll add ".00" to the shorter
87 # strings so that we're comparing strings of equal length
88 # Thus we'll compare libfoo.so.09.07.00 with
89 # libfoo.so.10.01.00. Some libraries might have letters
90 # in the version. We don't know what they mean, but will
91 # try to skip them gracefully -- we'll set any letter to
92 # '0'. Finally, sort in reverse so we can take the
95 #TODO: iterate through the directory instead of sorting
97 $fullname = "$thispth/" .
100 $ma =~ tr/A-Za-z/0/s;
101 $ma =~ s/\b(\d)\b/0$1/g;
102 $mb =~ tr/A-Za-z/0/s;
103 $mb =~ s/\b(\d)\b/0$1/g;
104 while (length($ma) < length($mb)) { $ma .= ".00"; }
105 while (length($mb) < length($ma)) { $mb .= ".00"; }
106 # Comparison deliberately backwards
107 $mb cmp $ma;} @fullname)[0];
108 } elsif (-f ($fullname="$thispth/lib$thislib.$so")
109 && (($Config{'dlsrc'} ne "dl_dld.xs") || ($thislib eq "m"))){
110 } elsif (-f ($fullname="$thispth/lib${thislib}_s$Config_libext")
111 && ($thislib .= "_s") ){ # we must explicitly use _s version
112 } elsif (-f ($fullname="$thispth/lib$thislib$Config_libext")){
113 } elsif (-f ($fullname="$thispth/$thislib$Config_libext")){
114 } elsif (-f ($fullname="$thispth/Slib$thislib$Config_libext")){
115 } elsif ($^O eq 'dgux'
116 && -l ($fullname="$thispth/lib$thislib$Config_libext")
117 && readlink($fullname) =~ /^elink:/) {
118 # Some of DG's libraries look like misconnected symbolic
119 # links, but development tools can follow them. (They
122 # libm.a -> elink:${SDE_PATH:-/usr}/sde/\
123 # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a
125 # , the compilation tools expand the environment variables.)
127 warn "$thislib not found in $thispth\n" if $verbose;
130 warn "'-l$thislib' found at $fullname\n" if $verbose;
131 my($fullnamedir) = dirname($fullname);
132 push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++;
136 # Now update library lists
138 # what do we know about this library...
139 my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/);
140 my $in_perl = ($libs =~ /\B-l\Q$ {thislib}\E\b/s);
142 # Do not add it into the list if it is already linked in
143 # with the main perl executable.
144 # We have to special-case the NeXT, because math and ndbm
145 # are both in libsys_s
147 ($Config{'osname'} eq 'next' &&
148 ($thislib eq 'm' || $thislib eq 'ndbm')) ){
149 push(@extralibs, "-l$thislib");
152 # We might be able to load this archive file dynamically
153 if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0')
154 || ($Config{'dlsrc'} =~ /dl_dld/) )
156 # We push -l$thislib instead of $fullname because
157 # it avoids hardwiring a fixed path into the .bs file.
158 # Mkbootstrap will automatically add dl_findfile() to
159 # the .bs file if it sees a name in the -l format.
160 # USE THIS, when dl_findfile() is fixed:
161 # push(@bsloadlibs, "-l$thislib");
162 # OLD USE WAS while checking results against old_extliblist
163 push(@bsloadlibs, "$fullname");
166 # For SunOS4, do not add in this shared library if
167 # it is already linked in the main perl executable
168 push(@ldloadlibs, "-l$thislib")
169 unless ($in_perl and $^O eq 'sunos');
171 push(@ldloadlibs, "-l$thislib");
174 last; # found one here so don't bother looking further
176 warn "Note (probably harmless): "
177 ."No library found for -l$thislib\n"
180 return ('','','','') unless $found;
181 ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path));
186 require Text::ParseWords;
188 my($self, $potential_libs, $verbose) = @_;
190 # If user did not supply a list, we punt.
191 # (caller should probably use the list in $Config{libs})
192 return ("", "", "", "") unless $potential_libs;
194 my $cc = $Config{cc};
195 my $VC = 1 if $cc =~ /^cl/i;
196 my $BC = 1 if $cc =~ /^bcc/i;
197 my $GC = 1 if $cc =~ /^gcc/i;
198 my $so = $Config{'so'};
199 my $libs = $Config{'libs'};
200 my $libpth = $Config{'libpth'};
201 my $libext = $Config{'lib_ext'} || ".lib";
203 if ($libs and $potential_libs !~ /:nodefault/i) {
204 # If Config.pm defines a set of default libs, we always
205 # tack them on to the user-supplied list, unless the user
206 # specified :nodefault
208 $potential_libs .= " " if $potential_libs;
209 $potential_libs .= $libs;
211 warn "Potential libraries are '$potential_libs':\n" if $verbose;
213 # normalize to forward slashes
215 $potential_libs =~ s,\\,/,g;
217 # compute $extralibs from $potential_libs
219 my @searchpath; # from "-L/path" in $potential_libs
220 my @libpath = Text::ParseWords::quotewords('\s+', 0, $libpth);
222 my $pwd = cwd(); # from Cwd.pm
226 my($fullname, $thislib, $thispth);
228 foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){
232 # see if entry is a flag
234 $search = 0 if lc eq ':nosearch';
235 $search = 1 if lc eq ':search';
236 warn "Ignoring unknown flag '$thislib'\n"
237 if $verbose and !/^:(no)?(search|default)$/i;
241 # if searching is disabled, do compiler-specific translations
243 s/^-L/-libpath:/ if $VC;
244 s/^-l(.+)$/$1.lib/ unless $GC;
245 push(@extralibs, $_);
250 # handle possible linker path arguments
251 if (s/^-L// and not -d) {
252 warn "$thislib ignored, directory does not exist\n"
257 unless ($self->file_name_is_absolute($_)) {
258 warn "Warning: '$thislib' changed to '-L$pwd/$_'\n";
259 $_ = $self->catdir($pwd,$_);
261 push(@searchpath, $_);
265 # handle possible library arguments
266 if (s/^-l// and $GC and !/^lib/i) {
269 $_ .= $libext if !/\Q$libext\E$/i;
274 # look for the file itself
276 warn "'$thislib' found as '$_'\n" if $verbose;
278 push(@extralibs, $_);
283 foreach $thispth (@searchpath, @libpath){
284 unless (-f ($fullname="$thispth\\$_")) {
285 warn "'$thislib' not found as '$fullname'\n" if $verbose;
288 warn "'$thislib' found as '$fullname'\n" if $verbose;
291 push(@extralibs, $fullname);
295 # do another pass with (or without) leading 'lib' if they used -l
296 if (!$found_lib and $thislib =~ /^-l/) {
297 if ($GC) { s/^lib//i }
298 else { $_ = "lib$_" }
299 goto LOOKAGAIN unless $secondpass++;
303 warn "Note (probably harmless): "
304 ."No library found for '$thislib'\n"
309 return ('','','','') unless $found;
311 # make sure paths with spaces are properly quoted
312 @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs;
313 $lib = join(' ',@extralibs);
315 # normalize back to backward slashes (to help braindead tools)
316 # XXX this may break equally braindead GNU tools that don't understand
317 # backslashes, either. Seems like one can't win here. Cursed be CP/M.
320 warn "Result: $lib\n" if $verbose;
321 wantarray ? ($lib, '', $lib, '') : $lib;
326 my($self, $potential_libs,$verbose) = @_;
328 my($dbgqual) = $self->{OPTIMIZE} || $Config{'optimize'} ||
329 $self->{CCFLAS} || $Config{'ccflags'};
330 @crtls = ( ($dbgqual =~ m-/Debug-i ? $Config{'dbgprefix'} : '')
332 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libs'});
333 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libc'});
334 # In general, we pass through the basic libraries from %Config unchanged.
335 # The one exception is that if we're building in the Perl source tree, and
336 # a library spec could be resolved via a logical name, we go to some trouble
337 # to insure that the copy in the local tree is used, rather than one to
338 # which a system-wide logical may point.
339 if ($self->{PERL_SRC}) {
340 my($lib,$locspec,$type);
341 foreach $lib (@crtls) {
342 if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and $locspec =~ /perl/i) {
343 if (lc $type eq '/share') { $locspec .= $Config{'exe_ext'}; }
344 elsif (lc $type eq '/library') { $locspec .= $Config{'lib_ext'}; }
345 else { $locspec .= $Config{'obj_ext'}; }
346 $locspec = $self->catfile($self->{PERL_SRC},$locspec);
347 $lib = "$locspec$type" if -e $locspec;
351 $crtlstr = @crtls ? join(' ',@crtls) : '';
353 unless ($potential_libs) {
354 warn "Result:\n\tEXTRALIBS: \n\tLDLOADLIBS: $crtlstr\n" if $verbose;
355 return ('', '', $crtlstr, '');
358 my(@dirs,@libs,$dir,$lib,%sh,%olb,%obj,$ldlib);
360 my($so,$lib_ext,$obj_ext) = @Config{'so','lib_ext','obj_ext'};
361 # List of common Unix library names and there VMS equivalents
362 # (VMS equivalent of '' indicates that the library is automatially
363 # searched by the linker, and should be skipped here.)
364 my %libmap = ( 'm' => '', 'f77' => '', 'F77' => '', 'V77' => '', 'c' => '',
365 'malloc' => '', 'crypt' => '', 'resolv' => '', 'c_s' => '',
366 'socket' => '', 'X11' => 'DECW$XLIBSHR',
367 'Xt' => 'DECW$XTSHR', 'Xm' => 'DECW$XMLIBSHR',
368 'Xmu' => 'DECW$XMULIBSHR');
369 if ($Config{'vms_cc_type'} ne 'decc') { $libmap{'curses'} = 'VAXCCURSE'; }
371 warn "Potential libraries are '$potential_libs'\n" if $verbose;
373 # First, sort out directories and library names in the input
374 foreach $lib (split ' ',$potential_libs) {
375 push(@dirs,$1), next if $lib =~ /^-L(.*)/;
376 push(@dirs,$lib), next if $lib =~ /[:>\]]$/;
377 push(@dirs,$lib), next if -d $lib;
378 push(@libs,$1), next if $lib =~ /^-l(.*)/;
381 push(@dirs,split(' ',$Config{'libpth'}));
383 # Now make sure we've got VMS-syntax absolute directory specs
384 # (We don't, however, check whether someone's hidden a relative
385 # path in a logical name.)
386 foreach $dir (@dirs) {
388 warn "Skipping nonexistent Directory $dir\n" if $verbose > 1;
392 warn "Resolving directory $dir\n" if $verbose;
393 if ($self->file_name_is_absolute($dir)) { $dir = $self->fixpath($dir,1); }
394 else { $dir = $self->catdir($cwd,$dir); }
396 @dirs = grep { length($_) } @dirs;
397 unshift(@dirs,''); # Check each $lib without additions first
399 LIB: foreach $lib (@libs) {
400 if (exists $libmap{$lib}) {
401 next unless length $libmap{$lib};
402 $lib = $libmap{$lib};
405 my(@variants,$variant,$name,$test,$cand);
408 # If we don't have a file type, consider it a possibly abbreviated name and
409 # check for common variants. We try these first to grab libraries before
410 # a like-named executable image (e.g. -lperl resolves to perlshr.exe
412 if ($lib !~ /\.[^:>\]]*$/) {
413 push(@variants,"${lib}shr","${lib}rtl","${lib}lib");
414 push(@variants,"lib$lib") if $lib !~ /[:>\]]/;
416 push(@variants,$lib);
417 warn "Looking for $lib\n" if $verbose;
418 foreach $variant (@variants) {
419 foreach $dir (@dirs) {
422 $name = "$dir$variant";
423 warn "\tChecking $name\n" if $verbose > 2;
424 if (-f ($test = VMS::Filespec::rmsexpand($name))) {
425 # It's got its own suffix, so we'll have to figure out the type
426 if ($test =~ /(?:$so|exe)$/i) { $type = 'sh'; }
427 elsif ($test =~ /(?:$lib_ext|olb)$/i) { $type = 'olb'; }
428 elsif ($test =~ /(?:$obj_ext|obj)$/i) {
429 warn "Note (probably harmless): "
430 ."Plain object file $test found in library list\n";
434 warn "Note (probably harmless): "
435 ."Unknown library type for $test; assuming shared\n";
439 elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or
440 -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) {
442 $name = $test unless $test =~ /exe;?\d*$/i;
444 elsif (not length($ctype) and # If we've got a lib already, don't bother
445 ( -f ($test = VMS::Filespec::rmsexpand($name,$lib_ext)) or
446 -f ($test = VMS::Filespec::rmsexpand($name,'.olb')))) {
448 $name = $test unless $test =~ /olb;?\d*$/i;
450 elsif (not length($ctype) and # If we've got a lib already, don't bother
451 ( -f ($test = VMS::Filespec::rmsexpand($name,$obj_ext)) or
452 -f ($test = VMS::Filespec::rmsexpand($name,'.obj')))) {
453 warn "Note (probably harmless): "
454 ."Plain object file $test found in library list\n";
456 $name = $test unless $test =~ /obj;?\d*$/i;
459 $ctype = $type; $cand = $name;
460 last if $ctype eq 'sh';
464 eval '$' . $ctype . "{'$cand'}++";
465 die "Error recording library: $@" if $@;
466 warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1;
470 warn "Note (probably harmless): "
471 ."No library found for $lib\n";
474 @libs = sort keys %obj;
475 # This has to precede any other CRTLs, so just make it first
476 if ($olb{VAXCCURSE}) {
477 push(@libs,"$olb{VAXCCURSE}/Library");
478 delete $olb{VAXCCURSE};
480 push(@libs, map { "$_/Library" } sort keys %olb);
481 push(@libs, map { "$_/Share" } sort keys %sh);
482 $lib = join(' ',@libs);
484 $ldlib = $crtlstr ? "$lib $crtlstr" : $lib;
485 warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose;
486 wantarray ? ($lib, '', $ldlib, '') : $lib;
495 ExtUtils::Liblist - determine libraries to use and how to use them
499 C<require ExtUtils::Liblist;>
501 C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose);>
505 This utility takes a list of libraries in the form C<-llib1 -llib2
506 -llib3> and prints out lines suitable for inclusion in an extension
507 Makefile. Extra library paths may be included with the form
508 C<-L/another/path> this will affect the searches for all subsequent
511 It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS,
512 LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything
513 on VMS and Win32. See the details about those platform specifics
516 Dependent libraries can be linked in one of three ways:
520 =item * For static extensions
522 by the ld command when the perl binary is linked with the extension
523 library. See EXTRALIBS below.
525 =item * For dynamic extensions
527 by the ld command when the shared object is built/linked. See
530 =item * For dynamic extensions
532 by the DynaLoader when the shared object is loaded. See BSLOADLIBS
539 List of libraries that need to be linked with when linking a perl
540 binary which includes this extension Only those libraries that
541 actually exist are included. These are written to a file and used
544 =head2 LDLOADLIBS and LD_RUN_PATH
546 List of those libraries which can or must be linked into the shared
547 library when created using ld. These may be static or dynamic
548 libraries. LD_RUN_PATH is a colon separated list of the directories
549 in LDLOADLIBS. It is passed as an environment variable to the process
550 that links the shared library.
554 List of those libraries that are needed but can be linked in
555 dynamically at run time on this platform. SunOS/Solaris does not need
556 this because ld records the information (from LDLOADLIBS) into the
557 object file. This list is used to create a .bs (bootstrap) file.
561 This module deals with a lot of system dependencies and has quite a
562 few architecture specific B<if>s in the code.
564 =head2 VMS implementation
566 The version of ext() which is executed under VMS differs from the
567 Unix-OS/2 version in several respects:
573 Input library and path specifications are accepted with or without the
574 C<-l> and C<-L> prefices used by Unix linkers. If neither prefix is
575 present, a token is considered a directory to search if it is in fact
576 a directory, and a library to search for otherwise. Authors who wish
577 their extensions to be portable to Unix or OS/2 should use the Unix
578 prefixes, since the Unix-OS/2 version of ext() requires them.
582 Wherever possible, shareable images are preferred to object libraries,
583 and object libraries to plain object files. In accordance with VMS
584 naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl;
585 it also looks for I<lib>lib and libI<lib> to accomodate Unix conventions
586 used in some ported software.
590 For each library that is found, an appropriate directive for a linker options
591 file is generated. The return values are space-separated strings of
592 these directives, rather than elements used on the linker command line.
596 LDLOADLIBS contains both the libraries found based on C<$potential_libs> and
597 the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those
598 libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH
603 In addition, an attempt is made to recognize several common Unix library
604 names, and filter them out or convert them to their VMS equivalents, as
607 In general, the VMS version of ext() should properly handle input from
608 extensions originally designed for a Unix or VMS environment. If you
609 encounter problems, or discover cases where the search could be improved,
612 =head2 Win32 implementation
614 The version of ext() which is executed under Win32 differs from the
615 Unix-OS/2 version in several respects:
621 If C<$potential_libs> is empty, the return value will be empty.
622 Otherwise, the libraries specified by C<$Config{libs}> (see Config.pm)
623 will be appended to the list of C<$potential_libs>. The libraries
624 will be searched for in the directories specified in C<$potential_libs>
625 as well as in C<$Config{libpth}>. For each library that is found, a
626 space-separated list of fully qualified library pathnames is generated.
630 Input library and path specifications are accepted with or without the
631 C<-l> and C<-L> prefices used by Unix linkers.
633 An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look
634 for the libraries that follow.
636 An entry of the form C<-lfoo> specifies the library C<foo>, which may be
637 spelled differently depending on what kind of compiler you are using. If
638 you are using GCC, it gets translated to C<libfoo.a>, but for other win32
639 compilers, it becomes C<foo.lib>. If no files are found by those translated
640 names, one more attempt is made to find them using either C<foo.a> or
641 C<libfoo.lib>, depending on whether GCC or some other win32 compiler is
642 being used, respectively.
644 If neither the C<-L> or C<-l> prefix is present in an entry, the entry is
645 considered a directory to search if it is in fact a directory, and a
646 library to search for otherwise. The C<$Config{lib_ext}> suffix will
647 be appended to any entries that are not directories and don't already have
650 Note that the C<-L> and <-l> prefixes are B<not required>, but authors
651 who wish their extensions to be portable to Unix or OS/2 should use the
652 prefixes, since the Unix-OS/2 version of ext() requires them.
656 Entries cannot be plain object files, as many Win32 compilers will
657 not handle object files in the place of libraries.
661 Entries in C<$potential_libs> beginning with a colon and followed by
662 alphanumeric characters are treated as flags. Unknown flags will be ignored.
664 An entry that matches C</:nodefault/i> disables the appending of default
665 libraries found in C<$Config{libs}> (this should be only needed very rarely).
667 An entry that matches C</:nosearch/i> disables all searching for
668 the libraries specified after it. Translation of C<-Lfoo> and
669 C<-lfoo> still happens as appropriate (depending on compiler being used,
670 as reflected by C<$Config{cc}>), but the entries are not verified to be
671 valid files or directories.
675 The libraries specified may be a mixture of static libraries and
676 import libraries (to link with DLLs). Since both kinds are used
677 pretty transparently on the win32 platform, we do not attempt to
678 distinguish between them.
682 LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS
683 and LD_RUN_PATH are always empty (this may change in future).
687 You must make sure that any paths and path components are properly
688 surrounded with double-quotes if they contain spaces. For example,
689 C<$potential_libs> could be (literally):
691 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib"
693 Note how the first and last entries are protected by quotes in order
694 to protect the spaces.
698 Since this module is most often used only indirectly from extension
699 C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add
700 a set of libraries to the build process for an extension:
704 When using GCC, that entry specifies that MakeMaker should first look
705 for C<libgl.a> (followed by C<gl.a>) in all the locations specified by
708 When using a compiler other than GCC, the above entry will search for
709 C<gl.lib> (followed by C<libgl.lib>).
711 Here is a less often used example:
713 LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32']
715 This specifies a search for library C<gl> as before. If that search
716 fails to find the library, it looks at the next item in the list. The
717 C<:nosearch> flag will prevent searching for the libraries that follow,
718 so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>,
719 since GCC can use that value as is with its linker.
721 When using the Visual C compiler, the second item is returned as
722 C<-libpath:d:\mesalibs mesa.lib user32.lib>.
724 When using the Borland compiler, the second item is returned as
725 C<-Ld:\mesalibs mesa.lib user32.lib>.
732 L<ExtUtils::MakeMaker>