Enforce strict C99 in Autoconf project

[John X]

Hello.

I have a program written in C and it uses Autoconf. It uses
AC_PROG_CC_C99 in configure.ac which when used with gcc translates to
the -std=gnu99 compiler option. The program is however written
somewhat strictly according to the C99 specification and does not use
any GNU extensions. From what I understand -std=c99 -pedantic is more
in line with what I want it to do.

How should I set up Autoconf in order to make the compiler enforce
that? Does it support this scenario or do I have to specify the
compiler options for all possible compilers?

- John