Ensure we can still build with C89.

.github/configs

@@ -22,6 +22,12 @@ LIBCRYPTOFLAGS=""
 case "$config" in
     default|sol64)
 	;;
+    c89)
+	CC="gcc"
+	CFLAGS="-Wall -std=c89 -pedantic -Werror=vla"
+	CONFIGFLAGS="--without-openssl --without-zlib"
+	TEST_TARGET=t-exec
+	;;
     kitchensink)
 	CONFIGFLAGS="--with-kerberos5 --with-libedit --with-pam"
 	CONFIGFLAGS="${CONFIGFLAGS} --with-security-key-builtin --with-selinux"

.github/workflows/c-cpp.yml

@@ -23,6 +23,7 @@ jobs:
           - { os: ubuntu-20.04, configs: valgrind-3 }
           - { os: ubuntu-20.04, configs: valgrind-4 }
           - { os: ubuntu-20.04, configs: valgrind-unit }
+          - { os: ubuntu-20.04, configs: c89 }
           - { os: ubuntu-20.04, configs: pam }
           - { os: ubuntu-20.04, configs: kitchensink }
           - { os: ubuntu-20.04, configs: hardenedmalloc }