package/speex: force arm mode instead of Thumb mode

Fix the following build failure:

/tmp/cclxE0xY.s: Assembler messages:
/tmp/cclxE0xY.s:118: Error: cannot honor width suffix -- `smlabb r2,r0,r4,r6'
/tmp/cclxE0xY.s:134: Error: cannot honor width suffix -- `smlabb r9,r2,r2,r3'
/tmp/cclxE0xY.s:812: Error: cannot honor width suffix -- `smlabb r1,r2,r2,r6'
/tmp/cclxE0xY.s:1202: Error: cannot honor width suffix -- `smulbb r3,r0,r6'
/tmp/cclxE0xY.s:2298: Error: cannot honor width suffix -- `smulbb r3,r0,r4'
/tmp/cclxE0xY.s:3133: Error: cannot honor width suffix -- `smulbb r3,r2,r5'

Fixes:
http://autobuild.buildroot.net/results/c55/c557ca72832c942f201b4a21f913f74534857cc6/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 17cdf58f1cb85a786cdd884872486828fe416112)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/speex/speex.mk

@@ -26,6 +26,10 @@ ifeq ($(BR2_PACKAGE_SPEEX_ARM5E),y)
 SPEEX_CONF_OPTS += --enable-arm5e-asm
 endif
 
+ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
+SPEEX_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -marm"
+endif
+
 define SPEEX_LIBTOOL_FIXUP
 	$(SED) 's|^hardcode_libdir_flag_spec=.*|hardcode_libdir_flag_spec=""|g' $(@D)/libtool
 	$(SED) 's|^runpath_var=LD_RUN_PATH|runpath_var=DIE_RPATH_DIE|g' $(@D)/libtool