vim-patch:8.1.0846: not easy to recognize the system Vim runs on

Problem:    Not easy to recognize the system Vim runs on.
Solution:   Add more items to the features list. (Ozaki Kiichi, closes vim/vim#3855)
https://github.com/vim/vim/commit/39536dd557e847e80572044c2be319db5886abe3

Some doc changes have already been applied. Some others are N/A.
"moon" was removed in patch 8.2.0427 so I did not add it.

5 files changed, 69 insertions, 21 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index bb04376f57..b0ce848de2 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -4347,6 +4347,9 @@ line({expr} [, {winid}])				*line()*
 			line("'t")		line number of mark t
 			line("'" . marker)	line number of mark marker
 <
+		To jump to the last known position when opening a file see
+		|last-position-jump|.
+
 		Can also be used as a |method|: >
 			GetValue()->line()
 
@@ -4912,8 +4915,10 @@ min({expr})	Return the minimum value of all items in {expr}.
 <							*mkdir()* *E739*
 mkdir({name} [, {path} [, {prot}]])
 		Create directory {name}.
+
 		If {path} is "p" then intermediate directories are created as
 		necessary.  Otherwise it must be "".
+
 		If {prot} is given it is used to set the protection bits of
 		the new directory.  The default is 0o755 (rwxr-xr-x: r/w for
 		the user, readable for others).  Use 0o700 to make it
@@ -4922,6 +4927,7 @@ mkdir({name} [, {path} [, {prot}]])
 		{prot} is applied for all parts of {name}.  Thus if you create
 		/tmp/foo/bar then /tmp/foo will be created with 0o700. Example: >
 			:call mkdir($HOME . "/tmp/foo/bar", "p", 0o700)
+
 <		This function is not available in the |sandbox|.
 
 		If you try to create an existing directory with {path} set to
@@ -5758,8 +5764,10 @@ remove({list}, {idx} [, {end}])				*remove()*
 		Example: >
 			:echo "last item: " . remove(mylist, -1)
 			:call remove(mylist, 0, 9)
+<
+		Use |delete()| to remove a file.
 
-<		Can also be used as a |method|: >
+		Can also be used as a |method|: >
 			mylist->remove(idx)
 
 remove({blob}, {idx} [, {end}])
@@ -5779,8 +5787,6 @@ remove({dict}, {key})
 			:echo "removed " . remove(dict, "one")
 <		If there is no {key} in {dict} this is an error.
 
-		Use |delete()| to remove a file.
-
 rename({from}, {to})					*rename()*
 		Rename the file by the name {from} to the name {to}.  This
 		should also work to move files across file systems.  The
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index f2b014dde6..d6486073cf 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -676,7 +676,7 @@ similar to -1. >
 	:let otherblob = myblob[:]	" make a copy of the Blob
 
 If the first index is beyond the last byte of the Blob or the second byte is
-before the first byte, the result is an empty Blob.  There is no error
+before the first index, the result is an empty Blob.  There is no error
 message.
 
 If the second index is equal to or greater than the length of the Blob the
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 29619f62e9..04a1f08f04 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -4433,6 +4433,12 @@ static void f_has(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 #if defined(BSD) && !defined(__APPLE__)
     "bsd",
 #endif
+#ifdef __linux__
+    "linux",
+#endif
+#ifdef SUN_SYSTEM
+    "sun",
+#endif
 #ifdef UNIX
     "unix",
 #endif
diff --git a/src/nvim/testdir/test_functions.vim b/src/nvim/testdir/test_functions.vim
index 0edbeb420a..e4c6c6a3b2 100644
--- a/src/nvim/testdir/test_functions.vim
+++ b/src/nvim/testdir/test_functions.vim
@@ -1377,6 +1377,35 @@ func Test_func_exists_on_reload()
   delfunc ExistingFunction
 endfunc
 
+func Test_platform_name()
+  " The system matches at most only one name.
+  let names = ['amiga', 'beos', 'bsd', 'hpux', 'linux', 'mac', 'qnx', 'sun', 'vms', 'win32', 'win32unix']
+  call assert_inrange(0, 1, len(filter(copy(names), 'has(v:val)')))
+
+  " Is Unix?
+  call assert_equal(has('beos'), has('beos') && has('unix'))
+  call assert_equal(has('bsd'), has('bsd') && has('unix'))
+  call assert_equal(has('hpux'), has('hpux') && has('unix'))
+  call assert_equal(has('linux'), has('linux') && has('unix'))
+  call assert_equal(has('mac'), has('mac') && has('unix'))
+  call assert_equal(has('qnx'), has('qnx') && has('unix'))
+  call assert_equal(has('sun'), has('sun') && has('unix'))
+  call assert_equal(has('win32'), has('win32') && !has('unix'))
+  call assert_equal(has('win32unix'), has('win32unix') && has('unix'))
+
+  if has('unix') && executable('uname')
+    let uname = system('uname')
+    call assert_equal(uname =~? 'BeOS', has('beos'))
+    call assert_equal(uname =~? 'BSD\|DragonFly', has('bsd'))
+    call assert_equal(uname =~? 'HP-UX', has('hpux'))
+    call assert_equal(uname =~? 'Linux', has('linux'))
+    call assert_equal(uname =~? 'Darwin', has('mac'))
+    call assert_equal(uname =~? 'QNX', has('qnx'))
+    call assert_equal(uname =~? 'SunOS', has('sun'))
+    call assert_equal(uname =~? 'CYGWIN\|MSYS', has('win32unix'))
+  endif
+endfunc
+
 sandbox function Fsandbox()
   normal ix
 endfunc
@@ -1519,24 +1548,31 @@ func Test_libcall_libcallnr()
     let libc = 'msvcrt.dll'
   elseif has('mac')
     let libc = 'libSystem.B.dylib'
-  elseif system('uname -s') =~ 'SunOS'
-    " Set the path to libc.so according to the architecture.
-    let test_bits = system('file ' . GetVimProg())
-    let test_arch = system('uname -p')
-    if test_bits =~ '64-bit' && test_arch =~ 'sparc'
-      let libc = '/usr/lib/sparcv9/libc.so'
-    elseif test_bits =~ '64-bit' && test_arch =~ 'i386'
-      let libc = '/usr/lib/amd64/libc.so'
+  elseif executable('ldd')
+    let libc = matchstr(split(system('ldd ' . GetVimProg())), '/libc\.so\>')
+  endif
+  if get(l:, 'libc', '') ==# ''
+    " On Unix, libc.so can be in various places.
+    if has('linux')
+      " There is not documented but regarding the 1st argument of glibc's
+      " dlopen an empty string and nullptr are equivalent, so using an empty
+      " string for the 1st argument of libcall allows to call functions.
+      let libc = ''
+    elseif has('sun')
+      " Set the path to libc.so according to the architecture.
+      let test_bits = system('file ' . GetVimProg())
+      let test_arch = system('uname -p')
+      if test_bits =~ '64-bit' && test_arch =~ 'sparc'
+        let libc = '/usr/lib/sparcv9/libc.so'
+      elseif test_bits =~ '64-bit' && test_arch =~ 'i386'
+        let libc = '/usr/lib/amd64/libc.so'
+      else
+        let libc = '/usr/lib/libc.so'
+      endif
     else
-      let libc = '/usr/lib/libc.so'
+      " Unfortunately skip this test until a good way is found.
+      return
     endif
-  elseif system('uname -s') =~ 'OpenBSD'
-    let libc = 'libc.so'
-  else
-    " On Unix, libc.so can be in various places.
-    " Interestingly, using an empty string for the 1st argument of libcall
-    " allows to call functions from libc which is not documented.
-    let libc = ''
   endif
 
   if has('win32')
diff --git a/src/nvim/testdir/test_writefile.vim b/src/nvim/testdir/test_writefile.vim
index aa7882d129..5ffbe82082 100644
--- a/src/nvim/testdir/test_writefile.vim
+++ b/src/nvim/testdir/test_writefile.vim
@@ -43,7 +43,7 @@ func Test_writefile_fails_gently()
 endfunc
 
 func Test_writefile_fails_conversion()
-  if !has('iconv') || system('uname -s') =~ 'SunOS'
+  if !has('iconv') || has('sun')
     return
   endif
   " Without a backup file the write won't happen if there is a conversion