package/audit: force arm mode instead of Thumb mode

Fix the following build failure:

/tmp/ccY5gl3z.s:2145: Error: selected processor does not support `mcr p15,0,r2,c7,c10,5' in Thumb mode

Fixes:
 - http://autobuild.buildroot.org/results/9d18a0d360b2e2f9e87c55daedda62d6ce198bb9

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/audit/audit.mk

@@ -15,6 +15,13 @@ AUDIT_INSTALL_STAGING = YES
 
 AUDIT_CONF_OPTS = --without-python --without-python3 --disable-zos-remote
 
+# src/libev has some assembly function that is not present in Thumb mode:
+# Error: selected processor does not support `mcr p15,0,r3,c7,c10,5' in Thumb mode
+# so, we desactivate Thumb mode
+ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
+AUDIT_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -marm"
+endif
+
 ifeq ($(BR2_PACKAGE_LIBCAP_NG),y)
 AUDIT_DEPENDENCIES += libcap-ng
 AUDIT_CONF_OPTS += --with-libcap-ng=yes