Added primitive support for the ISO C99 inline feature as well as the __inline__ extension.

No inlining is actually done but that part is not required by the standard.

test/val/inline-func.c

@@ -0,0 +1,20 @@
+/* C99 inline */
+
+#include <stdlib.h>
+
+inline static int f(int x, ...)
+{
+    return x * 2;
+}
+
+extern inline int g(int x);
+
+int main(void)
+{
+    return f(g(7)) == 42 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+int g(int x)
+{
+    return x * 3;
+}