configure: merge AC_CHECK_HEADERS calls

Also removed some pointless AC_SUBST invocation, which would only be
necessary if the Makefiles were using the results of the header
detection, which they are not.

Signed-off-by: Max Horn <max@quendi.de>

diff --git a/configure.ac b/configure.ac
index abc1640..022cba8 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -59,14 +59,7 @@ AC_C_INLINE
 AC_C_VARARRAYS
 AC_C_TYPEOF
 
-AC_CHECK_HEADERS(stdint.h)
-AC_SUBST(HAVE_STDINT_H)
-AC_CHECK_HEADERS(inttypes.h)
-AC_SUBST(HAVE_INTTYPES_H)
-AC_CHECK_HEADERS(byteswap.h)
-AC_SUBST(HAVE_BYTESWAP_H)
-
-AC_CHECK_HEADERS([sys/param.h])
+AC_CHECK_HEADERS([stdint.h inttypes.h byteswap.h sys/param.h])
 
 XIPH_C_BSWAP32