package/ltrace: do not enable libunwind support for MIPS

Currently libunwind support in ltrace is broken for MIPS. I'm working
with upstream to fix this issue, but it's not yet ready, so let's
disable it by now.

Fixes:

  http://autobuild.buildroot.net/results/79b/79b51941ed57b0564c68112489b03cac39a04e9a/

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ltrace/ltrace.mk

@@ -19,8 +19,9 @@ LTRACE_POST_PATCH_HOOKS += LTRACE_CREATE_CONFIG_M4
 
 # ltrace can use libunwind only if libc has backtrace() support
 # We don't normally do so for uClibc and we can't know if it's external
+# Also ltrace with libunwind support is broken for MIPS so we disable it
 ifeq ($(BR2_PACKAGE_LIBUNWIND),y)
-ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),)
+ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC)$(BR2_mips)$(BR2_mipsel),)
 # --with-elfutils only selects unwinding support backend. elfutils is a
 # mandatory dependency regardless.
 LTRACE_CONF_OPTS += --with-libunwind=yes --with-elfutils=no