package/mpg123: force arm mode instead of Thumb mode

Fix the following build failure:
Error: selected processor does not support `smull r3,ip,r2,r10' in Thumb mode

Fixes:
http://autobuild.buildroot.net/results/848/8484fc6be618f3edbf39a13928ab9a4b7b442235/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/mpg123/mpg123.mk

@@ -13,6 +13,13 @@ MPG123_LICENSE_FILES = COPYING
 MPG123_CPE_ID_VENDOR = mpg123
 MPG123_DEPENDENCIES = host-pkgconf
 
+# mpg123 has some assembly function that is not present in Thumb mode:
+# Error: selected processor does not support `smull r3,ip,r2,r10' in Thumb mode
+# so, we desactivate Thumb mode
+ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
+MPG123_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -marm"
+endif
+
 MPG123_CPU = $(if $(BR2_SOFT_FLOAT),generic_nofpu,generic_fpu)
 
 ifeq ($(BR2_aarch64),y)