Restore signature of `scm_search_path ()' as found in 1.8.

The incompatibly was introduced by
22f4ee48822db5e30df3abf9a11b6066f2bab9d3 ("make primitive-load-path load
compiled files if available").

* doc/ref/api-options.texi (Build Config): Update `search-path'
  documentation.

* libguile/load.c (scm_search_path): Change C prototype to expect only 3
  arguments.  Parse the rest argument accordingly.  Update callers.

* libguile/load.h (scm_search_path): Update accordingly.

1 files changed, 9 insertions, 3 deletions

diff --git a/doc/ref/api-options.texi b/doc/ref/api-options.texi
index f4caa8ac9..1b526a873 100644
--- a/doc/ref/api-options.texi
+++ b/doc/ref/api-options.texi
@@ -113,15 +113,21 @@ string, into a list and return the resulting list with
 is returned.
 @end deffn
 
-@deffn {Scheme Procedure} search-path path filename [extensions]
-@deffnx {C Function} scm_search_path (path, filename, extensions)
+@deffn {Scheme Procedure} search-path path filename [extensions [require-exts?]]
+@deffnx {C Function} scm_search_path (path, filename, rest)
 Search @var{path} for a directory containing a file named
 @var{filename}. The file must be readable, and not a directory.
 If we find one, return its full filename; otherwise, return
 @code{#f}.  If @var{filename} is absolute, return it unchanged.
 If given, @var{extensions} is a list of strings; for each
 directory in @var{path}, we search for @var{filename}
-concatenated with each @var{extension}.
+concatenated with each @var{extension}.  If @var{require-exts?}
+is true, require that the returned file name have one of the
+given extensions; if @var{require-exts?} is not given, it
+defaults to @code{#f}.
+
+For compatibility with Guile 1.8 and earlier, the C function takes only
+three arguments
 @end deffn
 
 @defvar %guile-build-info