[alsa-devel] [PATCH alsa-lib] utils/alsa.m4: conditionally enable libdl in AM_PATH_ALSA m4 macro

[Thomas Petazzoni]

From: Thomas De Schampheleire <thomas.de.schampheleire at gmail.com>

The AM_PATH_ALSA macro in utils/alsa.m4 unconditionally uses
-ldl. This breaks compilation of alsa-utils (and probably other
packages using this macro) for targets that do not support dynamic
loading.

This patch updates the macro to check if dlopen is available, and use
that result to conditionally add -ldl to the list of libraries.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire at gmail.com>
Signed-off-by: Jörg Krause <joerg.krause at embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 utils/alsa.m4 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/utils/alsa.m4 b/utils/alsa.m4
index e12310df..a5c5a292 100644
--- a/utils/alsa.m4
+++ b/utils/alsa.m4
@@ -44,6 +44,8 @@ if test "$alsa_inc_prefix" != "" ; then
 fi
 AC_MSG_RESULT($ALSA_CFLAGS)
 
+AC_CHECK_LIB(c, dlopen, LIBDL="", [AC_CHECK_LIB(dl, dlopen, LIBDL="-ldl")])
+
 dnl add any special lib dirs
 AC_MSG_CHECKING(for ALSA LDFLAGS)
 if test "$alsa_prefix" != "" ; then
@@ -52,7 +54,7 @@ if test "$alsa_prefix" != "" ; then
 fi
 
 dnl add the alsa library
-ALSA_LIBS="$ALSA_LIBS -lasound -lm -ldl -lpthread"
+ALSA_LIBS="$ALSA_LIBS -lasound -lm $LIBDL -lpthread"
 LIBS="$ALSA_LIBS $LIBS"
 AC_MSG_RESULT($ALSA_LIBS)
 
-- 
2.14.4