[gcc r16-5786] libcc1: Check for libgen.h header

[John David Anglin]

https://gcc.gnu.org/g:8de45537d29ee1c58ec4a2a50a0b511020bd919d

commit r16-5786-g8de45537d29ee1c58ec4a2a50a0b511020bd919d
Author: John David Anglin <danglin@gcc.gnu.org>
Date:   Sun Nov 30 20:51:13 2025 -0500

    libcc1: Check for libgen.h header
    
    The basename() function is declared in libgen.h.
    
    2025-11-30  John David Anglin  <danglin@gcc.gnu.org>
    
    libcc1/ChangeLog:
    
            * configure.ac: Check for libgen.h header.
            * configure: Regenerate.

Diff:
---
 libcc1/configure    | 12 ++++++++++++
 libcc1/configure.ac |  1 +
 2 files changed, 13 insertions(+)

diff --git a/libcc1/configure b/libcc1/configure
index 00cb83e0c39a..83468ea31c44 100755
--- a/libcc1/configure
+++ b/libcc1/configure
@@ -15298,6 +15298,18 @@ LDFLAGS="$cet_save_LDFLAGS"
 
 
 
+for ac_header in libgen.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "libgen.h" "ac_cv_header_libgen_h" "$ac_includes_default"
+if test "x$ac_cv_header_libgen_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBGEN_H 1
+_ACEOF
+
+fi
+
+done
+
 ac_fn_c_check_decl "$LINENO" "basename" "ac_cv_have_decl_basename" "$ac_includes_default"
 if test "x$ac_cv_have_decl_basename" = xyes; then :
   ac_have_decl=1
diff --git a/libcc1/configure.ac b/libcc1/configure.ac
index 87f157568e8b..287c65ead407 100644
--- a/libcc1/configure.ac
+++ b/libcc1/configure.ac
@@ -48,6 +48,7 @@ AC_SUBST(visibility)
 GCC_CET_HOST_FLAGS(CET_HOST_FLAGS)
 AC_SUBST(CET_HOST_FLAGS)
 
+AC_CHECK_HEADERS(libgen.h)
 AC_CHECK_DECLS([basename])
 
 GCC_BASE_VER