[RFC SBC] build: Add configure option --disable-high-precision

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This enables high precision using 64 bits accumulators by default which
can be disabled with --disable-high-precision.
---
 configure.ac     | 8 ++++++++
 sbc/sbc_tables.h | 2 --
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index c052616..5f994d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -58,4 +58,12 @@ if (test "${enable_tester}" != "no"); then
 fi
 AM_CONDITIONAL(TESTER, test "${enable_tester}" != "no")
 
+AC_ARG_ENABLE(high-precision, AC_HELP_STRING([--disable-high-precision],
+					[disable high precision support]),
+					[enable_high_precision=${enableval}])
+if (test "${enable_high_precision}" != "no"); then
+	AC_DEFINE(SBC_HIGH_PRECISION, 1,
+		[Define to 1 to enable high precision build of SBC encoder])
+fi
+
 AC_OUTPUT(Makefile sbc/sbc.pc)
diff --git a/sbc/sbc_tables.h b/sbc/sbc_tables.h
index 25e24e6..3fd80e1 100644
--- a/sbc/sbc_tables.h
+++ b/sbc/sbc_tables.h
@@ -136,8 +136,6 @@ static const int32_t synmatrix8[16][8] = {
 	  SN8(0xfb8e3130), SN8(0xf8275a10), SN8(0xfe70747c), SN8(0x06a6d988) }
 };
 
-/* Uncomment the following line to enable high precision build of SBC encoder */
-
 /* #define SBC_HIGH_PRECISION */
 
 #ifdef SBC_HIGH_PRECISION
-- 
1.8.3.1