Use ignorestatus() and isnothing() (instead of using try-catch)

src/PackageCompiler.jl

@@ -712,15 +712,7 @@ function create_sysimg_from_object_file(object_files::Vector{String},
     mkpath(dirname(sysimage_path))
     # Prevent compiler from stripping all symbols from the shared lib.
     if Sys.isapple()
-        try
-            cltools_version_cmd = `pkgutil --pkg-info=com.apple.pkg.CLTools_Executables`
-            cltools_version = match(r"version: (.*)\n", readchomp(cltools_version_cmd))[1]
-            global major_version = split(cltools_version, ".")[1]
-        catch e
-            @warn "Could not determine the version of the Command Line Tools, assuming greater than 14"
-            global major_version = "15"
-        end
-        if parse(Int64, major_version) > 14
+        if _xcode_clt_major_version() > 14
             o_file_flags = `-Wl,-all_load $object_files -Wl,-ld_classic`
         else
             o_file_flags = `-Wl,-all_load $object_files`
@@ -734,6 +726,24 @@ function create_sysimg_from_object_file(object_files::Vector{String},
     return nothing
 end
 
+function _xcode_clt_major_version()
+    cmd = `pkgutil --pkg-info=com.apple.pkg.CLTools_Executables`
+    @debug "_xcode_clt_major_version(): Attempting to run command" cmd
+    # The `ignorestatus` allows us to proceed (with a warning) if
+    # the command does not run successfully.
+    output = strip(read(ignorestatus(cmd), String)) * "\n"
+    r = r"version: (.*)\n"
+    m = match(r, output)
+    if isnothing(m)
+        @warn "Could not determine the version of the Command Line Tools, assuming greater than 14"
+        major_version_str = "15"
+    else
+        major_version_str = split(m[1], '.')[1]
+    end
+    major_version_int = parse(Int, major_version_str)
+    return major_version_int
+end
+
 function get_extra_linker_flags(version, compat_level, soname)
     current_ver_arg = ``
     compat_ver_arg = ``