[opus] Opus 1.1: configure uses invalid shell syntax

[Christian Weisgerber]

configure uses invalid shell syntax.  (Ah, it's a bash extension.)
Here's a portable fix.

--- configure.ac.orig	Thu Dec  5 00:26:45 2013
+++ configure.ac	Sun Dec 15 17:32:25 2013
@@ -333,9 +333,9 @@ AS_IF([test x"${enable_asm}" = x"yes"],[
 
 AM_CONDITIONAL([CPU_ARM], [test "$cpu_arm" = "yes"])
 AM_CONDITIONAL([OPUS_ARM_INLINE_ASM],
-    [test x"${inline_optimization:0:3}" = x"ARM"])
+    [expr x"${inline_optimization}" : x"ARM" >/dev/null])
 AM_CONDITIONAL([OPUS_ARM_EXTERNAL_ASM],
-    [test x"${asm_optimization:0:3}" = x"ARM"])
+    [expr x"${asm_optimization}" : x"ARM" >/dev/null])
 
 AS_IF([test x"$enable_rtcd" = x"yes"],[
     AS_IF([test x"$rtcd_support" != x"no"],[
-- 
Christian "naddy" Weisgerber                          naddy at mips.inka.de