Added more stringent check for C99 support in configure script. (#9982)

This will help ensure that people who are building on a compiler that
does not support C99 get a more useful message about needing C99 and
also avoid wasting time getting into the build itself.

configure.ac

@@ -173,6 +173,10 @@ AC_ARG_ENABLE(
     [enable_ebpf="detect"]
 )
 
+# -----------------------------------------------------------------------------
+# Enforce building with C99, bail early if we can't.
+test "${ac_cv_prog_cc_c99}" = "no" && AC_MSG_ERROR([Netdata rquires a compiler that supports C99 to build])
+
 # -----------------------------------------------------------------------------
 # Check if cloud is enabled and if the functionality is available