make `cpp -gcc' the default on NetBSD.

gnu/dist/gcc/gcc/config/netbsd.h

@@ -234,3 +234,7 @@ __enable_execute_stack (addr)						\
   /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */				\
   (void) mprotect (page, end - page, 7);				\
 }
+
+/* NetBSD depends on "cpp" having GNUC semantics, and must default as if
+   "cpp -gcc" was called. */
+#define DEFAULT_CPP_NEED_NO_GCC 0

gnu/dist/gcc/gcc/cppspec.c

@@ -85,6 +85,13 @@ lang_specific_driver (in_argc, in_argv, in_added_libraries)
 
   is_cpp_driver = 1;
 
+  /* NetBSD uses __GNUC__ and friends in header files processed with cpp
+     regularly.  Default to old behaviour here. XXX - move me to
+     config/netbsd.h "DEFAULT_CPP_NEED_NO_GCC".  */
+#ifdef DEFAULT_CPP_NEED_NO_GCC
+  need_no_gcc = DEFAULT_CPP_NEED_NO_GCC;
+#endif
+
   /* First pass.  If we see an -S or -c, barf.  If we see an input file,
      turn off read_stdin.  If we see a second input file, it is actually
      the output file.  If we see a third input file, barf.  */