remove this obsolete file that has a lot of dated info from

about the time we started switching some ports to GCC 5.3.

external/gpl3/gcc.old/README.gcc53

@@ -1,108 +0,0 @@
-$NetBSD: README.gcc53,v 1.1.1.1 2017/07/23 01:04:23 mrg Exp $
-
-lib:
-	libasan is disabled currently (haven't tried yet)
-
-new stuff:
-	cc1objcplus
-	collect2 -- need to re-introduce?
-	libcilkrts
-	libmpx
-	liboffloadmic
-	libvtv
-	libitm
-
-other changes to look at:
-
-Index: gcc/targhooks.c
-	vs new binutils
-
-+           doc/gcov-tool.1
-
-
-arch/feature list.  anything not here has been switched already:
-
-tools:		does build.sh tools work?
-kernels:	does a kernel run?
-libgcc:		does libgcc build?
-native-gcc:	does a full mknative-gcc complete?
-make release:	does build.sh release complete? 
-runs:		does the system boot with a full world?
-atf:		does atf run / compare well
-
-
-architecture	tools	kernels	libgcc	native-gcc	make release	runs	atf
-------------	-----	-------	------	----------	------------	----	---
-arm		y	?	y	y		n[3]
-armeb		y	?	y	y		n[3]
-coldfire	y	N/A	y	y		?		N/A	N/A
-earm		y	?	y	y		y[3,13]
-earmeb		y	?	y	y		y[3,13]
-earmhf		y	?	y	y		y[3]
-earmhfeb	y	?	y	y		y[3]
-earmv4		y	y	y	y		y[3]		y	y
-earmv4eb	y	?	y	y		y[3]
-earmv6		y	?	y	y		y[3]
-earmv6eb	y	?	y	y		y[3]
-earmv6hf	y	?	y	y		y[3]
-earmv6hfeb	y	?	y	y		y[3]
-earmv7		y	?	y	y		y[3]
-earmv7eb	y	?	y	y		y[3]
-earmv7hf	y	?	y	y		y[3]
-earmv7hfeb	y	?	y	y		y[3]
-m68000		y	?	y	y		y
-m68k		y	y[16]	y	y		y[13]
-mipseb		y	y	y	y		y		y
-mipsel		y	y	y	y		y		y	y
-mips64eb	y	y	y	y		y[8]		y	y
-mips64el	y	?	y	y		y		y	y
-powerpc		y	y	y	y		y		y[6]	
-powerpc64	y	?	y	y		y
-sh3eb		y	?	y	y		y[5]
-sh3el		y	?	y	y		y
-sparc		y	y	y	y		y		y[6]
-sparc64		y	y	y	y		y		y[6,2]	y
-vax		y	y	y	y		y		y[15]	n
---
-or1k		n[10]
-riscv32		n[10]
-riscv64		n[10]
-ia64
-------------	-----	-------	------	----------	------------	----	---
-architecture	tools	kernels	libgcc	native-gcc	make release	runs	atf
-
-
-[2] - -O2 and -Os kernels hang, -O1 SIR reset
-	-- may be a SMP issue; ultra10 works, ultra45 SMP does not
-		-- try sb2000 (particularly with UP kernel.  u45 UP is shitty.)
-[3] - MKCOMPAT=no enabled currently, infact OABI seems to be broken.  the docs say it was only deprecated, but the options make broken stuff.
-[5] - sh3eb tries to use sh specific atomic config which doesn't work, has hand edited mknative output
-[6] - crtbeginS.o builds incorrectly with GCC 5.3 and -O2.  a hack for -O1 has been added.
-[8] - sgimips64 release build fails, mdsetimage'd gz'd kernels don't get built?
-[10] - needs to be re-merged with GCC 5.3 versions of these not-merged-to-mainline-gcc ports.
-[13] - builds tested:
-       - m68k: mvm68k amiga atari
-       - earm : shark evbarm*
-       - mipseb: sgimips evbmips
-       - mipsel: evbmips
-       - mips64eb: sgimips[fail] evbmips
-       - mips64el: evbmips
-[14] - machines tested:
-       - sparc ss20 (OK)
-       - sparc64 ultra45 (FAIL), ultra10 (OK), sb2000 (OK UP, FAIL SMP.)
-       - powerpc pegasosII (OK)
-       - alpha UP1000 (OK)
-       - arm shark (OK)
-       - evbmips gxemul MALTA
-		- had to implement some MIPS32 in gxemul to make this work
-       - pmax gxemul (OK)
-       - sgimips O2 (OK kernel -- but my O2 is not stable)
-       - i386/amd64 (OK)
-       - hppa (OK)
-       - amiga (OK)
-[15] - vax -- switched to GCC 5.3 already as it is less broken
-	- ssh is broken, was broken with 4.8
-	- there are too many -O0's we added because of mis-handled rtl
-	- the eh_frame stuff is probably busted, but it never worked?
-[16] - kernels tested:
-	- m68k: amiga