Append CFLAGS and LDFLAGS to their Config.pm counterparts in EU::CBui…

…lder

Since ExtUtils::CBuilder 0.27_04 (bleadperl commit 06e8058),
CFLAGS and LDFLAGS from the environment have overridden the Config.pm
ccflags and ldflags settings. This can cause binary incompatibilities
between the core Perl and extensions built with EU::CBuilder.

Append to the Config.pm values rather than overriding them.

dist/ExtUtils-CBuilder/lib/ExtUtils/CBuilder/Base.pm

@@ -40,11 +40,13 @@ sub new {
     $self->{config}{$k} = $v unless exists $self->{config}{$k};
   }
   $self->{config}{cc} = $ENV{CC} if defined $ENV{CC};
-  $self->{config}{ccflags} = $ENV{CFLAGS} if defined $ENV{CFLAGS};
+  $self->{config}{ccflags} = join(" ", $self->{config}{ccflags}, $ENV{CFLAGS})
+     if defined $ENV{CFLAGS};
   $self->{config}{cxx} = $ENV{CXX} if defined $ENV{CXX};
   $self->{config}{cxxflags} = $ENV{CXXFLAGS} if defined $ENV{CXXFLAGS};
   $self->{config}{ld} = $ENV{LD} if defined $ENV{LD};
-  $self->{config}{ldflags} = $ENV{LDFLAGS} if defined $ENV{LDFLAGS};
+  $self->{config}{ldflags} = join(" ", $self->{config}{ldflags}, $ENV{LDFLAGS})
+     if defined $ENV{LDFLAGS};
 
   unless ( exists $self->{config}{cxx} ) {
     my ($ccpath, $ccbase, $ccsfx ) = fileparse($self->{config}{cc}, qr/\.[^.]*/);

dist/ExtUtils-CBuilder/t/04-base.t

@@ -1,7 +1,7 @@
 #! perl -w
 
 use strict;
-use Test::More tests => 50;
+use Test::More tests => 64;
 use Config;
 use Cwd;
 use File::Path qw( mkpath );
@@ -328,6 +328,29 @@ is_deeply( $mksymlists_args,
     "_prepare_mksymlists_args(): got expected arguments for Mksymlists",
 );
 
+my %testvars = (
+    CFLAGS  => 'ccflags',
+    LDFLAGS => 'ldflags',
+);
+
+while (my ($VAR, $var) = each %testvars) {
+    local $ENV{$VAR};
+    $base = ExtUtils::CBuilder::Base->new( quiet => 1 );
+    ok( $base, "ExtUtils::CBuilder::Base->new() returned true value" );
+    isa_ok( $base, 'ExtUtils::CBuilder::Base' );
+    like($base->{config}{$var}, qr/\Q$Config{$var}/,
+        "honours $var from Config.pm");
+
+    $ENV{$VAR} = "-foo -bar";
+    $base = ExtUtils::CBuilder::Base->new( quiet => 1 );
+    ok( $base, "ExtUtils::CBuilder::Base->new() returned true value" );
+    isa_ok( $base, 'ExtUtils::CBuilder::Base' );
+    like($base->{config}{$var}, qr/\Q$ENV{$VAR}/,
+        "honours $VAR from the environment");
+    like($base->{config}{$var}, qr/\Q$Config{$var}/,
+        "doesn't override $var from Config.pm with $VAR from the environment");
+}
+
 #####
 
 for ($source_file, $object_file, $lib_file) {