Add patch headers

Also cleanup the flex patch a bit

sysa/coreutils-5.0/patches/ls-strcmp.patch

@@ -1,3 +1,5 @@
+strcoll() does not exist in mes libc, change it to strcmp.
+
 --- src/ls.c
 +++ src/ls.c
 @@ -2597,7 +2597,7 @@ xstrcoll (char const *a, char const *b)

sysa/coreutils-5.0/patches/mbstate.patch

@@ -1,3 +1,6 @@
+mbstate_t is a struct that is required. However, it is not defined by mes libc.
+This implementation was taken from glibc 2.32. 
+
 --- lib/quotearg.c	2002-11-23 07:08:10.000000000 +0000
 +++ lib/quotearg.c	2021-01-17 19:41:59.461095532 +0000
 @@ -21,6 +21,7 @@

sysa/coreutils-5.0/patches/modechange.patch

@@ -1,3 +1,6 @@
+modechange.h uses functions defined in sys/stat.h, so we need to move it to
+after sys/stat.h include.
+
 --- lib/modechange.c	2001-12-09 22:54:19.000000000 +0000
 +++ lib/modechange.c	2021-01-17 18:34:22.016427148 +0000
 @@ -28,8 +28,8 @@