Use MALLOC_CONF rather than malloc_conf for tests.

malloc_conf does not reliably work with MSVC, which complains of
"inconsistent dll linkage", i.e. its inability to support the
application overriding malloc_conf when dynamically linking/loading.
Work around this limitation by adding test harness support for per test
shell script sourcing, and converting all tests to use MALLOC_CONF
instead of malloc_conf.

test/test.sh.in

@@ -11,6 +11,18 @@ case @abi@ in
     ;;
 esac
 
+# Make a copy of the @JEMALLOC_CPREFIX@MALLOC_CONF passed in to this script, so
+# it can be repeatedly concatenated with per test settings.
+export MALLOC_CONF_ALL=${@JEMALLOC_CPREFIX@MALLOC_CONF}
+# Concatenate the individual test's MALLOC_CONF and MALLOC_CONF_ALL.
+export_malloc_conf() {
+  if [ "x${MALLOC_CONF}" != "x" -a "x${MALLOC_CONF_ALL}" != "x" ] ; then
+    export @JEMALLOC_CPREFIX@MALLOC_CONF="${MALLOC_CONF},${MALLOC_CONF_ALL}"
+  else
+    export @JEMALLOC_CPREFIX@MALLOC_CONF="${MALLOC_CONF}${MALLOC_CONF_ALL}"
+  fi
+}
+
 # Corresponds to test_status_t.
 pass_code=0
 skip_code=1
@@ -24,7 +36,22 @@ for t in $@; do
     echo
   fi
   echo "=== ${t} ==="
-  ${t}@exe@ @abs_srcroot@ @abs_objroot@
+  if [ -e "@srcroot@${t}.sh" ] ; then
+    # Source the shell script corresponding to the test in a subshell and
+    # execute the test.  This allows the shell script to set MALLOC_CONF, which
+    # is then used to set @JEMALLOC_CPREFIX@MALLOC_CONF (thus allowing the
+    # per test shell script to ignore the @JEMALLOC_CPREFIX@ detail).
+    $(enable_fill=@enable_fill@ \
+      enable_prof=@enable_prof@ \
+      enable_tcache=@enable_tcache@ \
+      . @srcroot@${t}.sh && \
+      export_malloc_conf && \
+      ${t}@exe@ @abs_srcroot@ @abs_objroot@)
+  else
+    $(export MALLOC_CONF= && \
+      export_malloc_conf &&
+      ${t}@exe@ @abs_srcroot@ @abs_objroot@)
+  fi
   result_code=$?
   case ${result_code} in
     ${pass_code})