--- src/gpg-error.h.in
+++ src/gpg-error.h.in
@@ -141,7 +141,7 @@
 
 
 /* GCC feature test.  */
-#if __GNUC__
+#if defined __GNUC__
 # define _GPG_ERR_GCC_VERSION (__GNUC__ * 10000 \
                                + __GNUC_MINOR__ * 100 \
                                + __GNUC_PATCHLEVEL__)
--- src/gpgrt-int.h
+++ src/gpgrt-int.h
@@ -359,7 +359,7 @@
 
 #if _WIN32
 /* Prototypes for w32-estream.c.  */
-struct cookie_io_functions_s _gpgrt_functions_w32_pollable;
+extern struct cookie_io_functions_s _gpgrt_functions_w32_pollable;
 int _gpgrt_w32_pollable_create (void *_GPGRT__RESTRICT *_GPGRT__RESTRICT cookie,
                                 unsigned int modeflags,
                                 struct cookie_io_functions_s next_functions,