Exposes --disable-float-api in autoconf

Makefile.am

@@ -22,7 +22,10 @@ else
 SILK_SOURCES += $(SILK_SOURCES_FLOAT)
 endif
 
+if DISABLE_FLOAT_API
+else
 OPUS_SOURCES += $(OPUS_SOURCES_FLOAT)
+endif
 
 if CPU_ARM
 CELT_SOURCES += $(CELT_SOURCES_ARM)

configure.ac

@@ -138,6 +138,17 @@ AS_IF([test "$enable_fixed_point_debug" = "yes"],[
   AC_DEFINE([FIXED_DEBUG], [1], [Debug fixed-point implementation])
 ])
 
+AC_ARG_ENABLE([float_api],
+    [AS_HELP_STRING([--disable-float-api],
+                    [compile without the floating point API (for machines with no float library)])],,
+    [enable_float_api=yes])
+
+AM_CONDITIONAL([DISABLE_FLOAT_API], [test "$enable_float_api" = "no"])
+
+AS_IF([test "$enable_float_api" = "no"],[
+  AC_DEFINE([DISABLE_FLOAT_API], [1], [Do not build the float API])
+])
+
 AC_ARG_ENABLE([custom-modes],
     [AS_HELP_STRING([--enable-custom-modes], [enable non-Opus modes, e.g. 44.1 kHz & 2^n frames])],,
     [enable_custom_modes=no])