diff --git a/src/interfaces/ecpg/compatlib/Makefile b/src/interfaces/ecpg/compatlib/Makefile
index 19b1e86e964..45c8f9462f4 100644
--- a/src/interfaces/ecpg/compatlib/Makefile
+++ b/src/interfaces/ecpg/compatlib/Makefile
@@ -18,7 +18,7 @@ SO_MAJOR_VERSION= 3
 SO_MINOR_VERSION= 2
 
 override CPPFLAGS := -I../include -I$(top_srcdir)/src/interfaces/ecpg/include \
-	-I$(libpq_srcdir) -I$(top_srcdir)/src/include/utils $(CPPFLAGS)
+	-I$(libpq_srcdir) -I$(top_srcdir)/src/include/utils -DFRONTEND $(CPPFLAGS)
 override CFLAGS += $(PTHREAD_CFLAGS)
 
 SHLIB_LINK = -L../ecpglib -lecpg -L../pgtypeslib -lpgtypes $(libpq) \
diff --git a/src/interfaces/ecpg/pgtypeslib/Makefile b/src/interfaces/ecpg/pgtypeslib/Makefile
index 5dd538a4074..7f71e1bc5cc 100644
--- a/src/interfaces/ecpg/pgtypeslib/Makefile
+++ b/src/interfaces/ecpg/pgtypeslib/Makefile
@@ -18,7 +18,7 @@ SO_MAJOR_VERSION= 3
 SO_MINOR_VERSION= 1
 
 override CPPFLAGS := -I../include -I$(top_srcdir)/src/interfaces/ecpg/include \
-	-I$(top_srcdir)/src/include/utils -I$(libpq_srcdir) $(CPPFLAGS)
+	-I$(top_srcdir)/src/include/utils -I$(libpq_srcdir) -DFRONTEND $(CPPFLAGS)
 override CFLAGS += $(PTHREAD_CFLAGS)
 
 # Need to recompile any libpgport object files
diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index 5361a5c41e1..fa97c79471d 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -241,6 +241,7 @@ sub mkvcbuild
 
     my $libecpgcompat =
       $solution->AddProject('libecpg_compat','dll','interfaces','src\interfaces\ecpg\compatlib');
+    $libecpgcompat->AddDefine('FRONTEND');
     $libecpgcompat->AddIncludeDir('src\interfaces\ecpg\include');
     $libecpgcompat->AddIncludeDir('src\interfaces\libpq');
     $libecpgcompat->UseDef('src\interfaces\ecpg\compatlib\compatlib.def');