Add patch headers

Also cleanup the flex patch a bit

sysa/bzip2-1.0.8/patches/coreutils.patch

@@ -1,4 +1,8 @@
-diff -r -N -U3 bzip2-1.0.8/Makefile bzip2-1.0.8/Makefile
+Disable all coreutils calls in the Makefile which we do not have at this
+point of the bootstrap. ranlib can be unconditionally disabled as we do not
+have it either.
+
+diff -r -N -U3 Makefile Makefile
 --- Makefile	2019-07-13 18:50:05.000000000 +0100
 +++ Makefile	2021-01-14 15:45:17.558516299 +0000
 @@ -21,7 +21,7 @@

sysa/bzip2-1.0.8/patches/mes-libc.patch

@@ -1,4 +1,9 @@
-diff -r -N -U3 bzip2-1.0.8/bzip2.c bzip2-1.0.8/bzip2.c
+mes libc has no time support, so we remove that.
+
+It also does not have fch{own,mod}, which we don't care about in the bootstrap
+anyway, so we can null-op those calls.
+
+diff -r -N -U3 bzip2.c bzip2.c
 --- bzip2.c	2019-07-13 18:50:05.000000000 +0100
 +++ bzip2.c	2021-01-14 14:11:40.160213521 +0000
 @@ -1051,12 +1051,9 @@
@@ -15,7 +20,7 @@ diff -r -N -U3 bzip2-1.0.8/bzip2.c bzip2-1.0.8/bzip2.c
     ERROR_IF_NOT_ZERO ( retVal );
  #  endif
  }
-diff -r -N -U3 bzip2-1.0.8/utime.h bzip2-1.0.8/utime.h
+diff -r -N -U3 utime.h utime.h
 --- utime.h	1970-01-01 01:00:00.000000000 +0100
 +++ utime.h	2021-01-14 18:11:11.253825037 +0000
 @@ -0,0 +1,2 @@