Fix: libnuma is prepended to LIBS

The default behavior, for AC_CHECK_LIB when the `action-if-found` is NOT
defined, is to prepend the library to LIBS. [1]

"
If action-if-found is not specified, the default action prepends
-llibrary to LIBS and defines ‘HAVE_LIBlibrary’ (in all capitals).
"

It is important to note that the LIBS variable is used for ALL linking.

This is normally not a problem for most distribution since they force
the use of `--as-needed` at the toolchain level (gcc specs) (for example
debian [2]). One could also pass the `--as-needed` flag manually but
libtool reorganize flags in the case of shared object creation [3].

In our case, we always explicitly state the dependencies via the *_LIBADD
automake clause. We do not rely on the LIBS variable.

Simply force the define of HAVE_LIBNUMA to prevent the prepending to
LIBS.

[1] https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Libraries.html
[2] https://salsa.debian.org/toolchain-team/gcc/-/blob/master/debian/patches/gcc-as-needed.diff
[3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=347650

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I33221d14b96482ff71672458097423289f6b9fc2

diff --git a/configure.ac b/configure.ac
index 86b1d052393846c8a7da13df2b5e1630cd602b09..b62542287f6fbbaedf7421f288c849253c40eb22 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -404,7 +404,9 @@ AE_IF_FEATURE_ENABLED([java-agent-all], [
 
 # The numa integration requires libnuma
 AE_IF_FEATURE_ENABLED([numa], [
-  AC_CHECK_LIB([numa], [numa_available], [], [
+  AC_CHECK_LIB([numa], [numa_available], [
+    AC_DEFINE([HAVE_LIBNUMA], [1], [Define to 1 if libnuma is available.])
+  ], [
     AC_MSG_ERROR([dnl
 libnuma is not available. Please either install it (e.g. libnuma-dev) or use
 [LDFLAGS]=-Ldir to specify the right location, or use --disable-numa configure