build: Don't write valgrind log files to tmp/ directory

Inherited from libguestfs, we wrote valgrind log files into the tmp/
directory during tests.  However this makes it very difficult to
connect a particular log file to a particular failing test.  As with
nbdkit let's just write the valgrind output to stderr, where it will
end up in the test log file (ie. tests/test-suite.log or tests/*.log).

Cherry picked from virt-v2v commit 1e0d615a883e4056b757d041a1ad1bbd39df3b3c.
I did not include the extra changes to the valgrind command line
(especially --show-leak-kinds=all) since that complicates the output.

Author: rwmjones

m4/guestfs-progs.m4

@@ -85,7 +85,7 @@ AS_IF([test "x$VALGRIND" != "xno"],[
     # --read-inline-info=no is a temporary workaround for RHBZ#1662656.
     # Note we run libtool, not $(LIBTOOL) since the latter expands to
     # libtool-kill-dependency-libs.sh
-    VG='libtool --mode=execute $(VALGRIND) --vgdb=no --log-file=$(abs_top_builddir)/tmp/valgrind-%q{T}-%p.log --leak-check=full --error-exitcode=119 --suppressions=$(abs_top_srcdir)/valgrind-suppressions --trace-children=no --child-silent-after-fork=yes --run-libc-freeres=no --read-inline-info=no'
+    VG='libtool --mode=execute $(VALGRIND) --vgdb=no --leak-check=full --error-exitcode=119 --suppressions=$(abs_top_srcdir)/valgrind-suppressions --trace-children=no --child-silent-after-fork=yes --run-libc-freeres=no --read-inline-info=no'
     ],[
     # No valgrind, so substitute VG with something that will break.
     VG=VALGRIND_IS_NOT_INSTALLED

run.in

@@ -57,10 +57,6 @@ prepend()
 s="$(cd @abs_srcdir@ && pwd)"
 b="$(cd @abs_builddir@ && pwd)"
 
-# Set T to current date & time (mainly for valgrind logfile name).
-T=`date +%Y%m%d.%H.%M.%S`
-export T
-
 # Set tmpdir and cachedir so the appliance doesn't conflict with
 # globally installed libguestfs.
 #
@@ -101,11 +97,14 @@ if [ -z "$VIRT_BUILDER_DIRS" ]; then
 fi
 
 # This is a cheap way to find some use-after-free and uninitialized
-# read problems when using glibc.
-random_val="$(@AWK@ 'BEGIN{srand(); print 1+int(255*rand())}' < /dev/null)"
-LD_PRELOAD="${LD_PRELOAD:+"$LD_PRELOAD:"}libc_malloc_debug.so.0"
-GLIBC_TUNABLES=glibc.malloc.check=1:glibc.malloc.perturb=$random_val
-export LD_PRELOAD GLIBC_TUNABLES
+# read problems when using glibc.  But if we are valgrinding then
+# don't use this because it can stop valgrind from working.
+if [ -z "$VG" ]; then
+    random_val="$(@AWK@ 'BEGIN{srand(); print 1+int(255*rand())}' < /dev/null)"
+    LD_PRELOAD="${LD_PRELOAD:+"$LD_PRELOAD:"}libc_malloc_debug.so.0"
+    GLIBC_TUNABLES=glibc.malloc.check=1:glibc.malloc.perturb=$random_val
+    export LD_PRELOAD GLIBC_TUNABLES
+fi
 
 # Do we have libtool?  If we have it then we can use it to make
 # running valgrind simpler.  However don't depend on it.

tmp/.gitignore

@@ -3,4 +3,3 @@
 /libguestfs??????/
 /run-*
 /v2vovl*.qcow2
-/valgrind-*.log