Fixes #86 "-l somelib.dll doesn't work in recent PAR::Packer versions"

par_setup_libpath() in myldr/mktmpdir.c used to set all known
"search path for DLLs" environment variables (e.g. LD_LIBRARY_PATH
on Linux). The search path is set up so that the first directory
searched is a packed executable's cache directory (where the shared
perl library will be extracted to, also all packed "external" DLLs).
In 2017 (by 2ac7078) it was changed to only set the variable
relevant for the OS where PAR::Packer was build on, given by
$Config{ldlibpthname}. But some perl distributions
(e.g. Strawberry on Windows) do not specify $Config{ldlibpthname}.

Hardwire "PATH" for MSWin32 and otherwise complain if this Config
variable is undefined.

Add t/85-ldlibpthname.t: check that the value of the environment
variable for searching for DLLs, usually $ENV{$Config{ldlibpthname}},
starts with the cache directory, $ENV{PAR_TEMP}.

MANIFEST

@@ -69,6 +69,7 @@ t/30-current_exec.t
 t/40-packer_cd_option.t
 t/80-doublecolon.t
 t/85-crt-glob.t
+t/85-ldlibpthname.t
 t/85-myfile.t
 t/86-xs-exe.t
 t/86-xs-par.t

myldr/Makefile.PL

@@ -230,10 +230,18 @@ WriteMakefile(
 
 sub MY::postamble
 {
+    # Strawberry perl doesn't set $Config{ldlibpthname}
+    my $ldlibpthname = $^O eq 'MSWin32' ? "PATH" : $Config{ldlibpthname};
+    unless ($ldlibpthname) {
+    warn "\$Config{ldlibpthname} is not available for your OS ($^O)".
+	 "- PAR::Packer functionality may be limited";
+	 $ldlibpthname = "Config_ldlibpthname_not_available";
+     }
+
     my $make_frag = <<"EOT";
 LD=$ld
 CC=$cc
-CFLAGS=$cflags -DLDLIBPTHNAME=\\"$Config{ldlibpthname}\\" -DPARL_EXE=\\"parl$exe\\" -DPAR_PACKER_VERSION=\\"\$(VERSION)\\"
+CFLAGS=$cflags -DLDLIBPTHNAME=$ldlibpthname -DPARL_EXE=parl$exe -DPAR_PACKER_VERSION=\$(VERSION)
 OPTIMIZE=$optimize
 LDFLAGS=$Config{ldflags}
 PERL_LDFLAGS=$ldflags

myldr/boot.c

@@ -253,7 +253,7 @@ void spawn_perl(const char *argv0, const char *my_perl, const char *stmpdir)
 }
 #endif
 
-char pp_version_info[] = "@(#) Packed by PAR::Packer " PAR_PACKER_VERSION;
+char pp_version_info[] = "@(#) Packed by PAR::Packer " stringify(PAR_PACKER_VERSION);
 
 /* the contents of this string (in the executable myldr/boot)
  * will be patched by script/par.pl if option "--clean" is used with pp

myldr/internals.c

@@ -51,7 +51,7 @@ XS(XS_Internals_PAR_BOOT) {
      * this scalar so that a packed script may refer to the version
      * of PAR::Packer it was built with.
      */
-    sv_setpv(get_sv("PAR::Packer::VERSION", GV_ADD), PAR_PACKER_VERSION);
+    sv_setpv(get_sv("PAR::Packer::VERSION", GV_ADD), stringify(PAR_PACKER_VERSION));
 
     TAINT_NOT;
 

myldr/mktmpdir.c

@@ -63,21 +63,20 @@ static int isSafeDir(const char* val)
 
 void par_setup_libpath( const char * stmpdir )
 {
-    const char *val = NULL;
-    char *ld_path = LDLIBPTHNAME;
-    char *ld_path_env = NULL;
+    const char *ldlibpthname = stringify(LDLIBPTHNAME);
+    const char *val;
 
-    if ( (val = par_getenv(ld_path)) == NULL || strlen(val) == 0 ) {
-        par_setenv(ld_path, stmpdir);
+    if ( (val = par_getenv(ldlibpthname)) == NULL || strlen(val) == 0 ) {
+        par_setenv(ldlibpthname, stmpdir);
     }
-    else if ( !strstr(val, stmpdir) ) {
+    else {
         /* prepend stmpdir to (value of) environment variable */
-        ld_path_env = malloc( 
+       char *new_val = malloc( 
             strlen(stmpdir) + strlen(path_sep) + strlen(val) + 1);
         sprintf(
-            ld_path_env, "%s%s%s",
+            new_val, "%s%s%s",
             stmpdir, path_sep, val);
-        par_setenv(ld_path, ld_path_env);
+        par_setenv(ldlibpthname, new_val);
     }
 }
 
@@ -252,11 +251,12 @@ char *par_mktmpdir ( char **argv ) {
 #else
 #define STREQ(a,b) (strcmp(a,b) == 0)
 #endif
+        const char *parl_exe = stringify(PARL_EXE);
 	int prog_len = strlen(progname);
-	int parl_len = strlen(PARL_EXE);
+	int parl_len = strlen(parl_exe);
 
 	if (prog_len >= parl_len
-	    && STREQ(progname + prog_len - parl_len, PARL_EXE)
+	    && STREQ(progname + prog_len - parl_len, parl_exe)
 	    && (prog_len == parl_len || progname[prog_len - parl_len - 1] == dir_sep[0])
 	    && argv[1]
 	    && strlen(argv[1]) >= 4

myldr/mktmpdir.h

@@ -67,6 +67,9 @@
 #define par_lstat stat
 #endif
 
+#define _stringify(s) #s
+#define stringify(s) _stringify(s)
+
 #if defined(WIN32) || defined(OS2)
 static const char *dir_sep = "\\";
 static const char *path_sep = ";";

t/85-ldlibpthname.t

@@ -0,0 +1,31 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Config;
+use Data::Dumper;
+
+use Test::More;
+require "./t/utils.pl";
+
+my $ldlibpthname = $^O eq 'MSWin32' ? "PATH" : $Config{ldlibpthname};
+
+plan skip_all => "\$Config{ldlibpthname} is not available for your OS ($^O)" unless $ldlibpthname;
+plan tests => 3;
+
+my $exe = pp_ok(-e => <<"...");
+    use Data::Dumper; 
+    my \$data = { 
+        par_temp => \$ENV{PAR_TEMP}, 
+        ldlibpth => \$ENV{$ldlibpthname},
+    };
+    print Data::Dumper->new([\$data], ['data'])->Indent(1)->Useqq(1)->Dump();
+...
+
+my ($out) = run_ok($exe);
+our $data;
+eval $out;
+ok($data->{ldlibpth} =~ /^\Q$data->{par_temp}\E($|\Q$Config{path_sep}\E)/,
+    "PAR_TEMP is first item in $ldlibpthname as seen by packed executable")
+    or diag($out);
+
+