Docs for Base.julia_cmd(). News and compat annotation

for #29858 (capture --inline flag in julia_cmd).

NEWS.md

@@ -61,6 +61,7 @@ Standard library changes
     the returned array ([#29670]).
   * The process id is appended to malloc log files in order to track memory allocations of
     multiple processes ([#29969]).
+  * `Base.julia_cmd` now propagates the `--inline=(yes|no)` flag ([#29858]).
 
 Compiler/Runtime improvements
 -----------------------------

base/util.jl

@@ -399,7 +399,16 @@ printstyled(io::IO, msg...; bold::Bool=false, color::Union{Int,Symbol}=:normal)
     with_output_color(print, color, io, msg...; bold=bold)
 printstyled(msg...; bold::Bool=false, color::Union{Int,Symbol}=:normal) =
     printstyled(stdout, msg...; bold=bold, color=color)
+"""
+    Base.julia_cmd(juliapath=joinpath(Sys.BINDIR::String, julia_exename()))
+
+Return a julia command similar to the one of the running process.
+Propagates the `--cpu-target`, `--sysimage`, --compile `, `--depwarn`
+and `--inline` command line arguments.
 
+!!! compat "Julia 1.1"
+    The `--inline` flag is only propagated in Julia 1.1 and later.
+"""
 function julia_cmd(julia=joinpath(Sys.BINDIR::String, julia_exename()))
     opts = JLOptions()
     cpu_target = unsafe_string(opts.cpu_target)