4 files changed, 16 insertions, 9 deletions
diff --git a/src/pl/plperl/SPI.xs b/src/pl/plperl/SPI.xs
index b98c547e8be..b2db3bd6949 100644
--- a/src/pl/plperl/SPI.xs
+++ b/src/pl/plperl/SPI.xs
@@ -10,9 +10,6 @@
 /* this must be first: */
 #include "postgres.h"
 
-/* Defined by Perl */
-#undef _
-
 /* perl stuff */
 #define PG_NEED_PERL_XSUB_H
 #include "plperl.h"
diff --git a/src/pl/plperl/Util.xs b/src/pl/plperl/Util.xs
index 686513d2e8d..47eba594155 100644
--- a/src/pl/plperl/Util.xs
+++ b/src/pl/plperl/Util.xs
@@ -12,13 +12,11 @@
 
 /* this must be first: */
 #include "postgres.h"
+
 #include "fmgr.h"
 #include "utils/builtins.h"
 #include "utils/bytea.h"       /* for byteain & byteaout */
 
-/* Defined by Perl */
-#undef _
-
 /* perl stuff */
 #define PG_NEED_PERL_XSUB_H
 #include "plperl.h"
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 5cb3a447291..2db13d30308 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -7,9 +7,6 @@
 
 #include "postgres.h"
 
-/* Defined by Perl */
-#undef _
-
 /* system stuff */
 #include <ctype.h>
 #include <fcntl.h>
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 09a77dc0b7b..e94a4c345bd 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -39,6 +39,11 @@
 #undef printf
 
 /*
+ * Perl scribbles on the "_" macro too.
+ */
+#undef _
+
+/*
  * ActivePerl 5.18 and later are MinGW-built, and their headers use GCC's
  * __inline__.  Translate to something MSVC recognizes. Also, perl.h sometimes
  * defines isnan, so undefine it here and put back the definition later if
@@ -140,6 +145,16 @@
 #define vprintf			pg_vprintf
 #define printf(...)		pg_printf(__VA_ARGS__)
 
+/*
+ * Put back "_" too; but rather than making it just gettext() as the core
+ * code does, make it dgettext() so that the right things will happen in
+ * loadable modules (if they've set up TEXTDOMAIN correctly).  Note that
+ * we can't just set TEXTDOMAIN here, because this file is used by more
+ * extensions than just PL/Perl itself.
+ */
+#undef _
+#define _(x) dgettext(TEXTDOMAIN, x)
+
 /* put back the definition of isnan if needed */
 #ifdef _MSC_VER
 #ifndef isnan