PATH defaults now act more like GNU and POSIX

When PATH is unset or empty, use the system default,
to be consistent with GNU/Linux and with POSIX.
If there is no system default do not default to "."
as that can be dangerous.
* src/callproc.c (init_callproc_1, init_callproc):
Default PATH to the null pointer, not the empty string.
* src/emacs.c (default_PATH): New function.
(find_emacs_executable, decode_env_path): Be consistent with POSIX
and with glibc about what to do when PATH is unset or empty.

1 files changed, 6 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 865e5e6b6d5..8f396403ba2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2755,6 +2755,12 @@ option, but can optionally return the equivalent of 'exec-suffixes' from
 a remote host.  It must be used in conjunction with the function
 'exec-path'.
 
++++
+** The 'exec-path' variable now uses same default PATH as other programs.
+That is, if the PATH environment variable is unset or empty, 'exec-path'
+now acts as if PATH is the system default, which is "/bin:/usr/bin"
+on GNU/Linux systems.
+
 
 * Changes in Emacs 31.1 on Non-Free Operating Systems