Try locate `readlink` first in pyenv-hooks, fix #2654 (#2655)

* Remove all use of `greadlink`, fix #2654

Signed-off-by: Harry Chen <i@harrychen.xyz>

* revert greadlink back in tests

---------

Signed-off-by: Harry Chen <i@harrychen.xyz>
Co-authored-by: Anton Petrov <anton.a.petrov@gmail.com>

libexec/pyenv

@@ -29,7 +29,7 @@ if enable -f "${BASH_SOURCE%/*}"/../libexec/pyenv-realpath.dylib realpath 2>/dev
 else
   [ -z "$PYENV_NATIVE_EXT" ] || abort "failed to load \`realpath' builtin"
 
-  READLINK=$(type -P greadlink readlink | head -n1)
+  READLINK=$(type -P readlink)
   [ -n "$READLINK" ] || abort "cannot find readlink - are you missing GNU coreutils?"
 
   resolve_link() {

libexec/pyenv-hooks

@@ -26,7 +26,7 @@ if ! enable -f "${BASH_SOURCE%/*}"/pyenv-realpath.dylib realpath 2>/dev/null; th
     echo "pyenv: failed to load \`realpath' builtin" >&2
     exit 1
   fi
-READLINK=$(type -P greadlink readlink | head -n1)
+READLINK=$(type -P readlink)
 if [ -z "$READLINK" ]; then
   echo "pyenv: cannot find readlink - are you missing GNU coreutils?" >&2
   exit 1

libexec/pyenv-versions

@@ -34,7 +34,7 @@ if ! enable -f "${BASH_SOURCE%/*}"/pyenv-realpath.dylib realpath 2>/dev/null; th
     exit 1
   fi
 
-  READLINK=$(type -P greadlink readlink | head -n1)
+  READLINK=$(type -P readlink)
   if [ -z "$READLINK" ]; then
     echo "pyenv: cannot find readlink - are you missing GNU coreutils?" >&2
     exit 1

plugins/python-build/bin/python-build

@@ -56,9 +56,14 @@ lib() {
 }
 lib "$1"
 
+READLINK=$(type -P readlink)
+if [ -z "$READLINK" ]; then
+  echo "pyenv: cannot find readlink - are you missing GNU coreutils?" >&2
+  exit 1
+fi
 
 resolve_link() {
-  $(type -P greadlink readlink | head -n1) "$1"
+  $READLINK "$1"
 }
 
 abs_dirname() {