--- configure.ac
+++ configure.ac
@@ -230,6 +230,12 @@
 fi
 AC_SUBST(SIMD_CFLAGS)
 
+dnl Some headers require the simd cflags (like altivec.h)
+save_CFLAGS="$CFLAGS"
+save_CPPFLAGS="$CPPFLAGS"
+CFLAGS="$CFLAGS $SIMD_CFLAGS"
+CPPFLAGS="$CPPFLAGS $SIMD_CFLAGS"
+
 dnl Checks for header files.
 AC_HEADER_STDC
 AC_CHECK_HEADERS([libintl.h malloc.h stddef.h stdlib.h string.h strings.h sys/time.h unistd.h limits.h c_asm.h intrinsics.h stdint.h mach/mach_time.h sys/sysctl.h altivec.h])
@@ -237,6 +243,10 @@
 dnl intrinsics.h: cray unicos
 dnl sys/sysctl.h: MacOS X altivec detection
 
+dnl restore normal flags
+CFLAGS="$save_CFLAGS"
+CPPFLAGS="$save_CPPFLAGS"
+
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
 AC_C_INLINE