LIBS="$LIBS_SOCKETS $LIBS"
AX_LIB_SOCKET_NSL
LIBS_server="$LIBS"
+MY_LIB_READLINE
### Checks for header files
# No multiple definitions of uninitialized global variables
MY_APPEND_COMPILE_FLAGS([-fno-common])
+# Reign in overzealous optimizers
+#
+# Contemporary compilers can squeeze out some extra performance by
+# assuming the program never executes code that has undefined behavior
+# according to the C standard. Unfortunately, this can break
+# programs. Pointing out that these programs are non-conforming is as
+# correct as it is unhelpful, at least as long as the compiler is
+# unable to diagnose the non-conformingness.
+#
+# Since keeping our programs working is a lot more important to us
+# than running them as fast as possible, forbid some assumptions that
+# are known to break real-world programs:
+#
+# * Aliasing: perfectly clean programs don't engage in type-punning,
+# and perfectly conforming programs do it only in full accordance
+# with the standard's (subtle!) aliasing rules. Neither kind of
+# perfection is realistic for us, therefore -fno-strict-aliasing.
+#
+# * Signed integer overflow: perfectly clean programs won't ever do
+# signed integer arithmetic that overflows. This is an imperfect
+# program, therefore -fno-strict-overflow.
+#
+MY_APPEND_COMPILE_FLAGS([dnl
+-fno-strict-aliasing dnl
+-fno-strict-overflow])
+
+# Emit extra code to check for buffer overflows
+# Could fall back to -fstack-protector when -fstack-protector-strong
+# isnt't supported, for users of older compilers. Doesn't seem worth
+# the trouble, though.
+# Some ports of the GNU toolchain reportedly support it in the
+# compiler, but not libc. Use a test program that makes the compiler
+# emit the extra stack checking code, and test it compiles and links.
+AX_APPEND_LINK_FLAGS([-fstack-protector-strong], [], [],
+ [AC_LANG_SOURCE([[
+int
+main(int argc, char *argv[])
+{
+ char arr[64], *dst = arr, *src = argv[0];
+ while ((*dst++ = *src++)) ;
+}
+ ]])])
+
### Checks for library functions