Move LONG_LINE_MAX definition to fileio.h

All users of the macro (except for one, in serialize.c), use the macro in
connection with read_line(), so they must include fileio.h.  Let's not play
libc games and require multiple header file to be included for the most common
use of a function.

The removal of def.h includes is not exact. I mostly went over the commits that
switch over to use read_line() and add def.h at the same time and reverted the
addition of def.h in those files.

src/basic/clock-util.c

@@ -12,7 +12,6 @@
 
 #include "alloc-util.h"
 #include "clock-util.h"
-#include "def.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "macro.h"

src/basic/def.h

@@ -74,6 +74,4 @@
                 "/usr/lib/" n                   \
                 _CONF_PATHS_SPLIT_USR(n))
 
-#define LONG_LINE_MAX (1U*1024U*1024U)
-
 #define HIGH_RLIMIT_MEMLOCK (1024ULL*1024ULL*64ULL)

src/basic/exec-util.c

@@ -9,7 +9,6 @@
 
 #include "alloc-util.h"
 #include "conf-files.h"
-#include "def.h"
 #include "env-util.h"
 #include "exec-util.h"
 #include "fd-util.h"

src/basic/fileio.c

@@ -15,7 +15,6 @@
 
 #include "alloc-util.h"
 #include "ctype.h"
-#include "def.h"
 #include "env-util.h"
 #include "escape.h"
 #include "fd-util.h"

src/basic/fileio.h

@@ -10,6 +10,8 @@
 #include "macro.h"
 #include "time-util.h"
 
+#define LONG_LINE_MAX (1U*1024U*1024U)
+
 typedef enum {
         WRITE_STRING_FILE_CREATE            = 1 << 0,
         WRITE_STRING_FILE_ATOMIC            = 1 << 1,

src/basic/hostname-util.c

@@ -8,7 +8,6 @@
 #include <unistd.h>
 
 #include "alloc-util.h"
-#include "def.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "hostname-util.h"

src/basic/mount-util.c

@@ -13,7 +13,6 @@
 #include <libmount.h>
 
 #include "alloc-util.h"
-#include "def.h"
 #include "escape.h"
 #include "extract-word.h"
 #include "fd-util.h"

src/basic/process-util.c

@@ -25,7 +25,6 @@
 
 #include "alloc-util.h"
 #include "architecture.h"
-#include "def.h"
 #include "escape.h"
 #include "fd-util.h"
 #include "fileio.h"

src/basic/time-util.c

@@ -14,7 +14,6 @@
 #include <unistd.h>
 
 #include "alloc-util.h"
-#include "def.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "fs-util.h"

src/basic/virt.c

@@ -11,7 +11,6 @@
 
 #include "alloc-util.h"
 #include "dirent-util.h"
-#include "def.h"
 #include "env-util.h"
 #include "fd-util.h"
 #include "fileio.h"