configure.ac: simplify argp check

Rewrite argp check using the same AC_SEARCH_LIBS based method used
earlier in the fts check.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>

diff --git a/ChangeLog b/ChangeLog
index 563af0d2a24971692e73413078b5226dfe4766fe..def6279a3c76c37587a90d65bab2fb1cac0ff468 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2020-12-11  Dmitry V. Levin  <ldv@altlinux.org>
 
+       * configure.ac: Rewrite argp check.
+
        * configure.ac (AC_MSG_FAILURE): Fix typo.
 
 2020-11-30  Dmitry V. Levin  <ldv@altlinux.org>

diff --git a/configure.ac b/configure.ac
index 6c3e05bfdd73bc5dd296f2cc7e6f34b62a6cbfd5..392f9155edd985de91d8dc3476a612f192745e62 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -520,29 +520,14 @@ if test "$ac_cv_implicit_fallthrough" = "yes"; then
                  [Defined if __attribute__((fallthrough)) is supported])
 fi
 
-dnl Check if we have argp available from our libc
-AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM(
-               [#include <argp.h>],
-               [int argc=1; char *argv[]={"test"}; argp_parse(0,argc,&argv,0,0,0); return 0;]
-               )],
-       [libc_has_argp="true"],
-       [libc_has_argp="false"]
-)
-
-dnl If our libc doesn't provide argp, then test for libargp
-if test "$libc_has_argp" = "false" ; then
-       AC_MSG_WARN("libc does not have argp")
-       AC_CHECK_LIB([argp], [argp_parse], [have_argp="true"], [have_argp="false"])
-
-       if test "$have_argp" = "false"; then
-               AC_MSG_ERROR("no libargp found")
-       else
-               argp_LDADD="-largp"
-       fi
-else
-       argp_LDADD=""
-fi
+saved_LIBS="$LIBS"
+AC_SEARCH_LIBS([argp_parse], [argp])
+LIBS="$saved_LIBS"
+case "$ac_cv_search_argp_parse" in
+        no) AC_MSG_FAILURE([failed to find argp_parse]) ;;
+        -l*) argp_LDADD="$ac_cv_search_argp_parse" ;;
+        *) argp_LDADD= ;;
+esac
 AC_SUBST([argp_LDADD])
 
 saved_LIBS="$LIBS"