* configure.ac: Require c99 via AC_PROG_CC_C99
rebuilt is the same order in which make processed them, and this is defined
to be true in the GNU make manual.
+* WARNING: New build requirement
+ GNU make utilizes facilities from GNU Gnulib: Gnulib requires certain C99
+ features in the C compiler and so these features are required by GNU make:
+ https://www.gnu.org/software/gnulib/manual/html_node/C99-features-assumed.html
+ The configure script should verify the compiler has these features.
+
* GNU Make can now be built for MS-Windows using the Tiny C tcc compiler.
\f
AC_USE_SYSTEM_EXTENSIONS
AC_PROG_CC
+# GNU Gnulib requires C99, so I guess we might as well too...
+AC_PROG_CC_C99
+
# Configure gnulib
gl_EARLY
gl_INIT