grep: -P: report input filename upon PCRE execution failure

Without this, it could be tedious to determine which input
file evokes a PCRE-execution-time failure.
* src/pcresearch.c (Pexecute): When failing, include the
error-provoking file name in the diagnostic.
* src/grep.c (input_filename): Make extern, since used above.
* src/search.h (input_filename): Declare.
* tests/filename-lineno.pl: Test for this.
($no_pcre): Factor out.
* NEWS (Bug fixes): Mention this.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/grep.c b/src/grep.c
index de7616a0..bd6ca53a 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -641,7 +641,7 @@ typedef size_t (*execute_fp_t) (void *, char const *, size_t, size_t *,
 static execute_fp_t execute;
 static void *compiled_pattern;
 
-static char const *
+char const *
 input_filename (void)
 {
   if (!filename)