configure: Remove check for include file string.h

It is not needed as there is already check for C99.

Author: pali

configure.ac

@@ -19,7 +19,7 @@ AC_CHECK_LIB(readline, readline, [ ])
 
 dnl Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS(fcntl.h sys/time.h unistd.h getopt.h string.h readline/readline.h)
+AC_CHECK_HEADERS(fcntl.h sys/time.h unistd.h getopt.h readline/readline.h)
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_INLINE