winmm: Avoid casting return value of Heap(Re)Alloc calls.

[Dan Kegel]

Debugged version:

--- a/configure.ac
+++ b/configure.ac
@@ -1715,6 +1715,20 @@ then
   if test "x$enable_maintainer_mode" = "xyes"
   then
       WINE_TRY_CFLAGS([-Werror])
+  else
+    dnl Enable -Werror when building from git on 32 bit x86 with a
known good version of gcc
+    case $host_cpu in
+      *i[[3456789]]86*)
+        if test "x${GCC}" = "xyes" && test -d $srcdir/.git
+        then
+          gcc_version=`$CC -v 2>&1 | grep "gcc version" | sed 's/gcc
version //'`
+          case $gcc_version in
+          4.[[3456]].*)
+            WINE_TRY_CFLAGS([-Werror]) ;;
+          esac
+        fi
+      ;;
+    esac
   fi

   dnl Check for ms_hook_prologue support