diff --git a/configure.ac b/configure.ac
index 0f4807ecf4..5fe0e423f6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -135,6 +135,31 @@ AM_CONDITIONAL(HAVE_MONO_CAIRO, test "x$have_monocairo" = "xyes")
 
 AM_CONDITIONAL(ENABLE_MONODOC, test "x$enable_monodoc" = "xyes")
 
+WIN64DEFINES=
+case "$host" in
+        x86_64-*-mingw*|x86_64-*-cygwin*)
+                WIN64DEFINES="-define:WIN64LONGS"
+                platform_win32=yes
+                AC_DEFINE(PLATFORM_WIN32,1,[Platform is Win32])
+                if test "x$cross_compiling" = "xno"; then
+                        CC="gcc -mno-cygwin -g"
+                        HOST_CC="gcc"
+                fi
+                ;;
+        *-*-mingw*|*-*-cygwin*)
+                platform_win32=yes
+                AC_DEFINE(PLATFORM_WIN32,1,[Platform is Win32])
+                if test "x$cross_compiling" = "xno"; then
+                        CC="gcc -mno-cygwin -g"
+                        HOST_CC="gcc"
+                fi
+                ;;
+        *)
+                platform_win32=no
+                ;;
+esac
+AC_SUBST(WIN64DEFINES)
+
 ## Check for the gapi programs
 #PKG_CHECK_MODULES(GAPI, gapi-2.0 >= $GLIBSHARP_REQUIRED_VERSION)
 
diff --git a/generator/Makefile.am b/generator/Makefile.am
index 57dc559a12..7c4dc7268f 100644
--- a/generator/Makefile.am
+++ b/generator/Makefile.am
@@ -66,5 +66,5 @@ EXTRA_DIST =					\
 CLEANFILES = gst-gapi_codegen.exe gst-gapi_codegen.exe.mdb
 
 gst-gapi_codegen.exe: $(build_sources)
-	$(CSC) -debug -out:gst-gapi_codegen.exe $(OFF_T_FLAGS) $(references) $(build_sources)
+	$(CSC) -debug -out:gst-gapi_codegen.exe $(WIN64DEFINES) $(OFF_T_FLAGS) $(references) $(build_sources)
 
diff --git a/gstreamer-sharp/Makefile.am b/gstreamer-sharp/Makefile.am
index c5b3be653c..b4e7dbb96e 100644
--- a/gstreamer-sharp/Makefile.am
+++ b/gstreamer-sharp/Makefile.am
@@ -158,7 +158,7 @@ $(KEYFILE): $(top_srcdir)/gstreamer-sharp.snk
 	cp $(top_srcdir)/gstreamer-sharp.snk .
 
 $(ASSEMBLY): $(build_sources) generated-stamp $(KEYFILE) $(plugin_csfiles)
-	$(CSC) -nowarn:0612 -debug -unsafe -out:$(ASSEMBLY) -target:library $(references) $(csc_build_sources) $(GENERATED_SOURCES) $(plugin_csfiles)
+	$(CSC) -nowarn:0612 -debug -unsafe -out:$(ASSEMBLY) -target:library $(references) $(csc_build_sources) $(GENERATED_SOURCES) $(plugin_csfiles) -define:GTK_SHARP_2_6 -define:GTK_SHARP_2_8 -define:GTK_SHARP_2_10 -define:GTK_SHARP_2_12 -define:GTK_SHARP_2_14
 
 plugins-update:
 	$(MAKE) -C coreplugins plugins-update