Don't rely on HAVE_STDINT_H et al. being defined

Not everyone who includes speexdsp_config_types.h will have a test
which defines those, and if we've chosen to use the stdint types at
configure time then we know exactly which header(s) are available, so
just choose the best one then and generate the header to use it.

This patch, including the above text, is copied from a commit in the
speex repository[1]. The original commit for speex was made by Ron
<ron@debian.org>.

[1] https://git.xiph.org/?p=speex.git;a=commitdiff;h=774c87d6cb7dd8dabdd17677fc6da753ecf4aa87Signed-off-by: Tanu Kaskinen <tanu.kaskinen@linux.intel.com>

configure.ac

@@ -334,6 +334,12 @@ AC_SUBST([USIZE16])
 AC_SUBST([SIZE32])
 AC_SUBST([USIZE32])
 
+AS_IF([test "$ac_cv_header_stdint_h" = "yes"],    [INCLUDE_STDINT="#include <stdint.h>"],
+      [test "$ac_cv_header_inttypes_h" = "yes"],  [INCLUDE_STDINT="#include <inttypes.h>"],
+      [test "$ac_cv_header_sys_types_h" = "yes"], [INCLUDE_STDINT="#include <sys/types.h>"])
+
+AC_SUBST([INCLUDE_STDINT])
+
 AC_CONFIG_FILES([
            Makefile libspeexdsp/Makefile doc/Makefile SpeexDSP.spec
            include/Makefile include/speex/Makefile speexdsp.pc

include/speex/speexdsp_config_types.h.in

 #ifndef __SPEEX_TYPES_H__
 #define __SPEEX_TYPES_H__
 
-#if defined HAVE_STDINT_H
-#  include <stdint.h>
-#elif defined HAVE_INTTYPES_H
-#  include <inttypes.h>
-#elif defined HAVE_SYS_TYPES_H
-#  include <sys/types.h>
-#endif
+@INCLUDE_STDINT@
 
 typedef @SIZE16@ spx_int16_t;
 typedef @USIZE16@ spx_uint16_t;