lang/gcc9: Update to the GCC 9.4 release

This fixes more than 190 bugs compared to GCC 9.3.

files/patch-gcc_dumpfile.c has made it upstream in the meantime, so
remove it on our end.

lang/gcc9/Makefile

@@ -1,8 +1,7 @@
 # Created by: Gerald Pfeifer <gerald@FreeBSD.org>
 
 PORTNAME=	gcc
-PORTVERSION=	9.3.0
-PORTREVISION=	3
+PORTVERSION=	9.4.0
 CATEGORIES=	lang
 MASTER_SITES=	GCC
 PKGNAMESUFFIX=	${SUFFIX}

lang/gcc9/distinfo

@@ -1,3 +1,3 @@
-TIMESTAMP = 1584289638
-SHA256 (gcc-9.3.0.tar.xz) = 71e197867611f6054aa1119b13a0c0abac12834765fe2d81f35ac57f84f742d1
-SIZE (gcc-9.3.0.tar.xz) = 70533868
+TIMESTAMP = 1622967410
+SHA256 (gcc-9.4.0.tar.xz) = c95da32f440378d7751dd95533186f7fc05ceb4fb65eb5b85234e6299eb9838e
+SIZE (gcc-9.4.0.tar.xz) = 72411232

lang/gcc9/files/patch-gcc_dumpfile.c

@@ -1,11 +0,0 @@
---- gcc/dumpfile.c.orig	2020-04-07 14:09:14 UTC
-+++ gcc/dumpfile.c
-@@ -2055,7 +2055,7 @@ temp_dump_context::temp_dump_context (bool forcibly_en
- 				      bool forcibly_enable_dumping,
- 				      dump_flags_t test_pp_flags)
- : m_context (),
--  m_saved (&dump_context ().get ())
-+  m_saved(&dump_context::get())
- {
-   dump_context::s_current = &m_context;
-   if (forcibly_enable_optinfo)