Revert "Remove array size hacks for Rust < 1.47"

This reverts commit 27ee6fe.

These array structure changes were breaking changes to the
public API and should not have landed without a major
version bump.

Author: cramertj

libc-test/build.rs

@@ -400,7 +400,8 @@ fn test_apple(target: &str) {
             // FIXME: the array size has been changed since macOS 10.15 ([8] -> [7]).
             ("statfs", "f_reserved") => true,
             ("__darwin_arm_neon_state64", "__v") => true,
-
+            // MAXPATHLEN is too big for auto-derive traits on arrays.
+            ("vnode_info_path", "vip_path") => true,
             ("ifreq", "ifr_ifru") => true,
             ("in6_ifreq", "ifr_ifru") => true,
             ("ifkpi", "ifk_data") => true,
@@ -2763,6 +2764,8 @@ fn test_freebsd(target: &str) {
             ("umutex", "m_owner") => true,
             // c_has_waiters field is a volatile int32_t
             ("ucond", "c_has_waiters") => true,
+            // is PATH_MAX long but tests can't accept multi array as equivalent.
+            ("kinfo_vmentry", "kve_path") => true,
 
             // a_un field is a union
             ("Elf32_Auxinfo", "a_un") => true,
@@ -2791,6 +2794,10 @@ fn test_freebsd(target: &str) {
             // Anonymous type.
             ("filestat", "next") => true,
 
+            // We ignore this field because we needed to use a hack in order to make rust 1.19
+            // happy...
+            ("kinfo_proc", "ki_sparestrings") => true,
+
             // `__sem_base` is a private struct field
             ("semid_ds", "__sem_base") => true,
 

src/unix/bsd/apple/mod.rs

@@ -939,7 +939,9 @@ s! {
 
     pub struct vnode_info_path {
         pub vip_vi: vnode_info,
-        pub vip_path: [::c_char; ::MAXPATHLEN as usize],
+        // Normally it's `vip_path: [::c_char; MAXPATHLEN]` but because libc supports an old rustc
+        // version, we go around this limitation like this.
+        pub vip_path: [[::c_char; 32]; 32],
     }
 
     pub struct proc_vnodepathinfo {

src/unix/bsd/freebsdlike/dragonfly/mod.rs

@@ -517,7 +517,7 @@ s_no_extra_traits! {
         pub mc_ownedfp: ::c_uint,
         __reserved: ::c_uint,
         __unused: [::c_uint; 8],
-        pub mc_fpregs: [::c_uint; 256],
+        pub mc_fpregs: [[::c_uint; 8]; 32],
     }
 
     pub struct ucontext_t {

src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs

@@ -166,7 +166,7 @@ s! {
         /// More thread name.
         pub ki_moretdname: [::c_char; ::MAXCOMLEN - ::TDNAMLEN + 1],
         /// Spare string space.
-        pub ki_sparestrings: [::c_char; 46],
+        pub ki_sparestrings: [[::c_char; 23]; 2], // little hack to allow PartialEq
         /// Spare room for growth.
         pub ki_spareints: [::c_int; ::KI_NSPARE_INT],
         /// Which cpu we are on.

src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs

@@ -173,7 +173,7 @@ s! {
         /// More thread name.
         pub ki_moretdname: [::c_char; ::MAXCOMLEN - ::TDNAMLEN + 1],
         /// Spare string space.
-        pub ki_sparestrings: [::c_char; 46],
+        pub ki_sparestrings: [[::c_char; 23]; 2], // little hack to allow PartialEq
         /// Spare room for growth.
         pub ki_spareints: [::c_int; ::KI_NSPARE_INT],
         /// Controlling tty dev.

src/unix/bsd/freebsdlike/freebsd/freebsd13/mod.rs

@@ -183,7 +183,7 @@ s! {
         /// More thread name.
         pub ki_moretdname: [::c_char; ::MAXCOMLEN - ::TDNAMLEN + 1],
         /// Spare string space.
-        pub ki_sparestrings: [::c_char; 46],
+        pub ki_sparestrings: [[::c_char; 23]; 2], // little hack to allow PartialEq
         /// Spare room for growth.
         pub ki_spareints: [::c_int; ::KI_NSPARE_INT],
         /// Controlling tty dev.

src/unix/bsd/freebsdlike/freebsd/freebsd14/mod.rs

@@ -183,7 +183,7 @@ s! {
         /// More thread name.
         pub ki_moretdname: [::c_char; ::MAXCOMLEN - ::TDNAMLEN + 1],
         /// Spare string space.
-        pub ki_sparestrings: [::c_char; 46],
+        pub ki_sparestrings: [[::c_char; 23]; 2], // little hack to allow PartialEq
         /// Spare room for growth.
         pub ki_spareints: [::c_int; ::KI_NSPARE_INT],
         /// Controlling tty dev.

src/unix/bsd/freebsdlike/freebsd/freebsd15/mod.rs

@@ -183,7 +183,7 @@ s! {
         /// More thread name.
         pub ki_moretdname: [::c_char; ::MAXCOMLEN - ::TDNAMLEN + 1],
         /// Spare string space.
-        pub ki_sparestrings: [::c_char; 46],
+        pub ki_sparestrings: [[::c_char; 23]; 2], // little hack to allow PartialEq
         /// Spare room for growth.
         pub ki_spareints: [::c_int; ::KI_NSPARE_INT],
         /// Controlling tty dev.

src/unix/bsd/freebsdlike/freebsd/mod.rs

@@ -457,7 +457,7 @@ s! {
         _kve_is_spare: [::c_int; 8],
         #[cfg(freebsd11)]
         _kve_is_spare: [::c_int; 12],
-        pub kve_path: [::c_char; ::PATH_MAX as usize],
+        pub kve_path: [[::c_char; 32]; 32],
     }
 
     pub struct __c_anonymous_filestat {

src/unix/bsd/freebsdlike/mod.rs

@@ -284,7 +284,7 @@ s! {
 
     pub struct accept_filter_arg {
         pub af_name: [::c_char; 16],
-        af_arg: [::c_char; 240],
+        af_arg: [[::c_char; 10]; 24],
     }
 
     pub struct ptrace_io_desc {