From 96b3e393d62fb56ca7e66cea92c14751ce35f561 Mon Sep 17 00:00:00 2001
Message-Id: <96b3e393d62fb56ca7e66cea92c14751ce35f561.1429739396.git.jen@redhat.com>
In-Reply-To: <933ebfcd0e18f4ed2c68553cf4bc257652872678.1429739396.git.jen@redhat.com>
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From: John Snow <jsnow@redhat.com>
Date: Mon, 6 Apr 2015 18:46:18 -0500
Subject: [CHANGE 05/11] configure: properly check if -lrt and -lm is needed
To: rhvirt-patches@redhat.com,
    jen@redhat.com

RH-Author: John Snow <jsnow@redhat.com>
Message-id: <1428345980-16249-4-git-send-email-jsnow@redhat.com>
Patchwork-id: 64721
O-Subject: [RHEL-6.7 qemu-kvm PATCH 3/5] configure: properly check if -lrt and -lm is needed
Bugzilla: 1208605
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Bandan Das <bsd@redhat.com>

From: Natanael Copa <natanael.copa@gmail.com>

Fixes build against uClibc.

uClibc provides 2 versions of clock_gettime(), one with realtime
support and one without (this is so you can avoid linking in -lrt
unless actually needed). This means that the clock_gettime() don't
need -lrt. We still need it for timer_create() so we check for this
function in addition.

We also need check if -lm is needed for isnan().

Both -lm and -lrt are needed for libs_qga.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
(cherry picked from commit 8bacde8d86a09699207d85d4bab06162aed18dc4)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Jeff E. Nelson <jen@redhat.com>

Conflicts:
	configure
        - Conflicts in context,
        - Existing -lrt probe sample program was slightly different.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 configure | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

Signed-off-by: Jeff E. Nelson <jen@redhat.com>
---
 configure | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index d09786a..dfcb906 100755
--- a/configure
+++ b/configure
@@ -2079,17 +2079,44 @@ if compile_prog "" "" ; then
 fi
 
 ##########################################
+# Do we need libm
+cat > $TMPC << EOF
+#include <math.h>
+int main(void) { return isnan(sin(0.0)); }
+EOF
+if compile_prog "" "" ; then
+  :
+elif compile_prog "" "-lm" ; then
+  LIBS="-lm $LIBS"
+  libs_qga="-lm $libs_qga"
+else
+  echo
+  echo "Error: libm check failed"
+  echo
+  exit 1
+fi
+
+##########################################
 # Do we need librt
+# uClibc provides 2 versions of clock_gettime(), one with realtime
+# support and one without. This means that the clock_gettime() don't
+# need -lrt. We still need it for timer_create() so we check for this
+# function in addition.
 cat > $TMPC <<EOF
 #include <signal.h>
 #include <time.h>
-int main(void) { clockid_t id; return clock_gettime(id, NULL); }
+int main(void) {
+  timer_create(CLOCK_REALTIME, NULL, NULL);
+  return clock_gettime(CLOCK_REALTIME, NULL);
+}
 EOF
 
 if compile_prog "" "" ; then
   :
-elif compile_prog "" "-lrt" ; then
+# we need pthread for static linking. use previous pthread test result
+elif compile_prog "" "-lrt $pthread_lib" ; then
   LIBS="-lrt $LIBS"
+  libs_qga="-lrt $libs_qga"
 fi
 
 if test "$darwin" != "yes" -a "$mingw32" != "yes" -a "$solaris" != yes -a \
-- 
2.1.0